HUMAN STRUCTURE
AND FUNCTION
HUMB1000
Unit Coordinator: Flavia di Pietro
Tutor: Giuseppe and Andrea
Wednesday 10am-12pm
2
Table of Contents
COMPENDIUM ONE: What is life? .................................... 3
Lecture Notes ..................................................... 3
Compendium 1 Lecture 1 of 3 – What is Life? P1: The
human body ............................................................... 3
Compendium 2 Lecture 2 of 3 – What is life? P2:
Anatomical terminology ............................................. 3
Compendium 3 Lecture 3 of 3 – What is life? P3
Serous membranes ..................................................... 4
Compendium 1 ................................................... 4
COMPENDIUM TWO: How do cells do what they do? ....... 4
Lecture Notes ..................................................... 4
Compendium 2 Lecture 1 of 4 – How do cells do what
they do? P1 Cells and organelles ................................ 4
Compendium 2 Lecture 2 of 4 – how do cells do what
they do? P2 Epithelial tissue....................................... 5
Compendium 2 Lecture 3 of 4 – how do cells do what
they do? P3 Connective tissue ................................... 5
Compendium 2 Lecture 4 of 4 – how do cells do what
they do? P4 Muscle and nervous tissue ..................... 6
Compendium 2 ................................................... 6
COMPENDIUM THREE: Are you what you eat? ................. 6
Lecture Notes ..................................................... 6
Compendium 3 Lecture 1 of 2 – Are you what you
eat? P1 Anatomy of the digestive system .................. 6
Compendium 3 Lecture 2 of 2 – Are you what you
eat? P2 Nutrition and macromolecules ...................... 8
COMPENDIUM FOUR: Why do we breathe? ....................10
Compendium Lecture 1 of 4 – Why do we breathe? P1
Anatomy of the respiratory system .......................... 10
Compendium 4 lecture 2 of 4 – Why do we breathe?
P2 Gas exchange ....................................................... 12
Compendium 4 Lecture 3 of 4 – Why do we breathe?
P3 Ventilation ........................................................... 12
Compendium 4 lecture 4 of 4 -Why do we breathe?
P2 Respiratory volumes and capacitates .................. 13
Compendium 5 – Lecture 4 of 4 How do we fuel our
body? P4 Kreb’s Cycle & Oxidative Phosphorylation 16
COMPENDIUM SIX: How do things get around the body? 17
Lecture ............................................................. 17
Compendium 6 – Lecture 1 of 2 How do things get
around the body? P1 Cardiovascular system – the
heart ......................................................................... 17
Compendium 6 – Lecture 2 of 2 How do things get
around the body? P2 Cardiovascular system – blood,
blood vessels and capillaries exchange .................... 18
COMPENDIUM SEVEN: How do we get rid of toxic waste?
....................................................................................... 19
Lecture ............................................................. 19
Compendium 7 – Lecture 1 of 2 How do we get rid of
toxic wastes? P1: the anatomy of the renal system . 19
Compendium 7 – Lecture 2 of 2 How do we get rid of
toxic wastes? P2: the physiology of the renal system
.................................................................................. 20
COMPENDIUM EIGHT: How do we control ourselves ...... 21
Lecture Notes ................................................... 21
Compendium 8 – Lecture 1 of 4 How do we control
ourselves? P1: Introduction to the nervous system . 21
Compendium 8 – Lecture 2 of 4 How do we control
ourselves? P2: Cells of the nervous system .............. 22
Compendium 8 – Lecture 3 of 4 How do we control
ourselves? P3: Electrical signals and action potentials
.................................................................................. 23
Compendium 8 – Lecture 4 of 4 How do we control of
ourselves? P4: Spinal reflex arcs ............................... 23
COMPENDIUM NINE: HOW DOES IT ALL WORK?............. 24
Lecture Notes ................................................... 24
Compendium 9 - Lecture 1 of 4 How does it all work?
P1: The spinal cord and spinal nerves ...................... 24
Compendium 9 – Lecture 2 of 4 How does it all Work?
P2: The brain and cranial nerves .............................. 24
Compendium 9 – Lecture 3 of 4 How does it all work?
P3: The autonomic nervous system ......................... 25
Compendium 9 – Lecture 4 of 4 – The endocrine
system....................................................................... 26
COMPENDIUM FIVE: How do we fuel our body? ..............14
COMPENDIUM TEN: HOW DO WE PROTECT OURSELVES?29
Lecture ............................................................. 14
LECTURE NOTES ................................................ 29
Compendium 5 – Lecture 1 of 4 How do we fuel our
body? P1 Transport across the cell membrane ........ 14
Compendium 5 - Lecture 2 of 4 How do we fuel our
body? P2 The movement of water (osmosis) ........... 15
Compendium 5 – Lecture 3 of 4 How do we fuel our
body? P3 Glycolysis .................................................. 15
Compendium 10 – How do we protect ourselves? –
Lecture 1 of 2 – P1: Immunity .................................. 29
Compendium 10 – How do we protect ourselves? –
Lecture 2 of 2 – P2: Lymphatics ................................ 32
3
COMPENDIUM ONE: What is life?
Lecture Notes
Compendium 1 Lecture 1 of 3 – What is Life? P1: The
human body
Anatomy
 Anatomy: the branch of science that deals with
structure of organisms and their parts
 Gross anatomy (microscopic): structures examined
without the aid of a microscope
o Systematic: the study by system
o Regional: study by region
 Surface of anatomy (macroscopic): the study of the
external form of the body
 Microscopic anatomy: study of structures under
microscope
o Cytology: cells
o Histology: tissues
 Developmental anatomy: study of structural change
that occurs in the body’s life span
Physiology
 Physiology: the branch of science that deals with the
normal function of living organisms (humans) and their
parts
 Levels of physiology:
o Molecular
o Cellular
o Systemic – neurophysiology, cardiovascular etc.
Structural and functional organisation of the human body
 Chemical level: how atoms interact and bind to form
molecules (e.g. DNA)
 Cellular level: molecules interact and bid to form
organelles (e.g. nucleus)
 Tissue levels: numerous similar cells and tissue round
them to form a tissue type
 Organ levels: 2 or more tissue types together form an
organ (e.g. bladder)
 Organ system level: a group of organs performing a
common function (e.g. urinary system – kidneys,
bladder etc.)
 Organism level: anything living thing considered as a
whole (e.g. child)
Characteristics of life
1. Organisation – specific interactions between
organism – perform functions
2. Metabolism – ability to use energy
3. Responsiveness – adjust changes in the
environment
4. Growth – overall enlargement of the organism
5. Reproduction – formation of new cells and new
organism
Homeostasis
 Homeostasis: maintenance of relatively constant
environment
o Fluctuate around a set point
o Slightly below / above the set point = normal
range
o Most occur by negative feedback mechanism
Compendium 2 Lecture 2 of 3 – What is life? P2:
Anatomical terminology
What is anatomical position?
 The standard reference to describe body parts
o Erect person with:
 Face directed forward
 Upper limbs hanging by side; palm
forward
 Lower limbs straight
 Supine: laying down face up
 Prone: laying down face down
Directional terms
 Superior: above/towards the head e.g. chin is superior
to the navel
 Inferior: towards the feet (caudal)
 Anterior: towards the front e.g. breast is anterior to
spine (ventral)
 Posterior: behind (dorsal)
 Distal: “far from”
 Medial: towards the midline
 Lateral: away from the midline
 Superficial: close to surface
 Deep: towards the interior of the body
Body planes
 Sagittal: separates left and right part – median plane is
mid-sagittal
 Frontal: (coronal) – separates anterior and posterior
parts
 Transverse (horizontal): separates superior and inferior
portion
 Oblique: doesn’t run parallel
Body cavities
 Closed to the outside and provide protection
 Contain our internal organs, or viscera
o Thoracic cavity – most superior (heart, trachea
and esophagus)
o Abdominal cavity – inferior to diaphragm
(stomach, pancreas etc.)
o Pelvic cavity – bladder, urethra etc) no define
boundaries AKA ‘abdominopelvic cavity’
Subdivision of abdomen
 Quadrants (4)
Right upper quadrant
Left upper quadrant
Right lower quadrant
Left lower quadrant
 Regions (9)
Right
hypochondriac
region
(liver, Gallbladder,
right kidney, small
intestine)
Right lumbar region
(Gallbladder, liver,
right colon)
Right iliac region
(appendix, cecum)
Epigastric region
(stomach, liver,
pancreas,
duodenum, spleen,
adrenal glands)
Umbilical region
(Umbilicus – navel,
parts of the small
intestine,
duodenum
Hypogastric region
(urinary bladder,
sigmoid colon,
female reproductive
organs)
Left
hypochondriac
region (Spleen,
colon, left
kidney,
pancreas)
Left lumbar
region
(Descending
colon, left
kidney)
Left iliac region
(Descending
colon, sigmoid
colon)
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Compendium 3 Lecture 3 of 3 – What is life? P3 Serous
membranes
Serous membranes
 Aka serosa
 Double-layered membranes
o Parietal serous membranes: lines the body
cavity
o Visceral serous membranes: lines the internal
organs
 Membranes separated by thin film of serous fluid –
produce by membranes which give friction reduction
 Pericardial cavity – parietal and visceral pericardium
with pericardial fluid
 Pleural cavity – parietal and visceral pleura with pleural
fluid
 Peritoneal cavity – parietal and visceral peritoneum
with peritoneal fluid
o Peri: around cardi: heart  the heart cavity
o Houses lungs and diaphragm
o Peritoneum – abdominal cavity
Compendium 1
o Cytoplasmic inclusion: aggregates of chemicals
The Nucleus & the cytoplasmic organelles
o Small, specialized structures
o Most have membranes
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COMPENDIUM TWO: How do cells do what
they do?
Lecture Notes
Compendium 2 Lecture 1 of 4 – How do cells do what they
do? P1 Cells and organelles
The cell
 Structural and functional unit of all living things,
including humans
 Plasma membrane, cytoplasm containing organelles,
nucleus
Functional characteristics of a cell
 Cell metabolism and energy use
 Synthesis of molecules (e.g. RNA)
 Communication
 Reproductive and inheritance
Plasma membrane
 Aka: cell membrane, sarcolemma, plasmalemma
 Function:
o Encloses and supports cellular content
o Controls what goes in and out
o Regulates intra vs. extracellular material
o Inter-cellular communication
o Production of a charge different across the
membrane
 Structure:
o Lipid bilayer
o Carbohydrates
o Proteins
o Fluid mosaic model
o Glycocalyx (outer surface of cell membrane)
o Glycoproteins (carbohydrates & proteins)
o Glycolipids
Cytoplasm
 Cellular fluid material outside nucleus but within
plasma membranes
Cytosol
 Fluid portion of cytoplasm (ions and proteins in water)
o Cytoskeleton: supports cells and its organelles
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Nucleus
o Control centre of the cell
o DNA
o Nuclear envelope: bilayer membrane
o Nucleoplasm
o Nucleolus – produces ribosomes
Chromosome structure
o Chromatid: DNA complexed with proteins
(histones)
Ribosomes
o Sites of protein synthesis
 Nucleolus, nucleus and cytoplasm
o Structure: 2 subunits (large and small)
Endoplasmic Reticulum
o Fattened, interconnecting sacs and tubules
o Rough ER – with ribosomes (synthesis and
modification of proteins)
o Smooth ER – without ribosomes (lipid, steroid
and carbs synthesis, detoxification of harmful
substances & glycogen  glucose)
Golgi Apparatus
o Structure: flattened membranal sacs with
cisternae
o Function: modifies, packages & distributes
proteins and lipids that are made in the rough
ER
Lysosomes
o Formed by the Golgi
o Contains enzyme
o “demolition crew”
o Digestion of molecules no longer needed by the
cell
Mitochondria
o Structure: outer membrane, intermembrane
space and inner membrane matrix
o Changes shape continually
o Has own genetic material
o Function: “power plants of the cell” – ATP
o Increases in number when cell energy
requirement increases
Centrioles
o Barrel shaped
o Wall composed of microtubules
o Cell division
Cilia
o Whip-like projection
o Move substances across the surface of cells
Flagella
o Longer than cilia – found on humans (sperms
cells only)
Microvilli
o 1/10 to 1/20 the size of the cilia: increases
surface area
Compendium 2 Lecture 2 of 4 – how do cells do what they
do? P2 Epithelial tissue
4 primary tissue types
 Epithelium, connective, muscle and nervous
Histology
 Study of tissue: thin slices of tissue (stain added)
Preparation of tissue
1. Removal of tissue via biopsy or autopsy
2. Fixation of tissue
3. Embedding of tissue: e.g. surrounded by wax
4. Slicing & mounting tissue on slide
5. Staining and viewing using a microscope
Haematoxylin and Eosin
 Abbreviated H&E
 Nuclei are stained purple (from H) others including
cytoplasm are stained pink (eosin)
Different histological images
 Frontal / coronal
 Transverse / horizontal
 Sagittal / median
Primary tissues
 Epithelial tissues: covers
 Connective tissue: supports
 Muscle tissue: movement
 Nervous tissue: controls
Epithelial tissue
 Covers and protects
 Types:
o Covering and lining
o Glandular
 Distinct cell surfaces
o Free surface
o Lateral surface
o Basal surface
 Avascular but innervated – nerve supply (avascular
means that it does not have a blood supply)
 Ability to regenerate
Cell layers
 Simple – single layer
 Stratified – more than 1 layer
 Pseudostratified – looks like 1 + layer but really is 1
layer
Cell shape
 Squamous: “paving stones” in surface view
 Cuboidal: cube with large round nucleus
 Columnar: tall cells with ovoid nuclei towards base
 Transitional: can change shape from columnar to
cuboidal
Examples of cell shapes & layers
 Simple squamous epithelium
o Diffusion, filtration and some secretion
o Alveoli of lungs, kidney glomeruli, serous
membrane of pleura
 Simple cuboidal epithelium
o Absorption, secretion and movement
o Intestines, stomach, fallopian tubes and lungs
 Transitional epithelium
o Accommodates changes in fluid volume of the
organs
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Urinary bladder, ureter and upper part of
urethra
 Stratified squamous epithelium
o Protection against abrasion and loss of water
 Keratinized (water proofing substance):
sole of feet, palm of hands, skin
 Non-keratinized: mouth, oesophagus,
anus and vagina
 Stratified cuboidal epithelium
o Absorption, secretion and protection
o Duct of sweat glands, salivary glands and
developing ovum
 Stratified columnar epithelium
o Secretion and protection
o Ducts of mammary glands, larynx and urethra
 Pseudo-stratified columnar epithelium
o Secretion and movement
o Pharynx, trachea, male’s sperm carrying ducts
 Exceptions to the rule (combinations that do not exist):
o Simple transitional
o Stratified transitional
o Pseudostratified squamous
o Pseudostratified cuboidal
o Pseudostratified transitional
Compendium 2 Lecture 3 of 4 – how do cells do what they
do? P3 Connective tissue
Connective tissue
 Most abundant and widely distributed
 Very diverse
 Functions:
o Connects and binds together, supports,
strengthens, protects, insulates,
compartmentalise, transports, provides energy
 Location
o All organs and parts but amount vary
 Composition
o Cells (produce extracellular matrix – ECM),
ground substance (ECM), fibres (ECM)
Cells of connective tissue
 Adipose cells – energy source and cushioning
 Fibroblast
 Mast cells
 White blood cells
 Macrophages
Ground substance
 Fills the spaces between the cells of connective tissue
 Fibres – collagen, elastic and reticular fibres
(supporting network)
Classes of Connective tissue
1. CONNECTIVE TISSUE PROPER
 Dense: Regular, irregular, elastic
 Loose: Areolar, adipose and reticular
 Areolar
o Loose packaging, support, and binding other
tissues
o Throughout body
 Adipose
o Nutrient-storing ability, shock absorption,
insulation
o Fat under skin  kidney, breast, abs and hips
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Reticular
o Framework to support free blood cells (white
blood cells, mast cells etc)
o Lymph nodes, spleen, bone marrow
 Regular
o Attachment: T bundles highly organise)
tendons and ligaments
 Irregular
o Strength and stretch in 3D directions
o Skin’s dermis, coverings surrounding bones, etc.
 Elastic
o Recoil & strength
o Aorta, arteries wall, spinal vertebrate
2. CARTILAGE
 Rigid matrix
 Avascular and not innervated
 Protection, flexibility, rigidity and withstand pressure
 Hyaline – rib cage, trachea, bones and nose surfaces
 Fibrocartilage – intervertebral discs and pubic
symphysis
 Elastic – ear and epiglottis
3. BONE
 Support and protect body structures
 Cell and matrix
 Osteocytes (bone cells)
 2 types:
o Spongy – ends of long bone, sternum, vertebrae
and pelvis
o Compact – shaft of long bone, makes up outer
portions of all cells
4. BLOOD
 Atypical connective tissue – doesn’t provide support or
“connect”
 Mostly red blood cells and white blood cells and
platelets
 Transports nutrients, wastes, respiratory gases around
the body
Compendium 2 Lecture 4 of 4 – how do cells do what they
do? P4 Muscle and nervous tissue
Muscle tissue
 Highly cellular, well vascularised and responsible for
tension and body movement
Types of muscle
 Skeletal muscle
o Attached to skeleton
o Heat regulation, metabolism, posture and
breathing
o Regenerate after injury
o Hypertrophy in response to exercise or get
smaller
o Muscle cells: muscle fibres / myofibres
o Striated muscle
o Multinucleated
o Peripheral nuclei
o Mostly voluntary control but involuntary may
occur (e.g. twitching)
 Cardiac muscle
o Involuntary
o Only found in walls of heart
o Generates pressure which moves blood
6
Change the rate and force of heart contractions
to meet metabolic needs
o 3 layers
 Epicardium – (visceral pericardium):
serous membrane underlying fatty
connective tissue
 Myocardium – middle muscle layer.
Majority cardiomyocytes
 Endocardium – inner layer. Endothelial
lining
o Striated muscle with intercalated disks
o Cardiac muscle cells: cardiomyocytes
o Cells are branched with central nuclei
o Lots of mitochondria
o Involuntary and cannot regenerate
 Smooth muscle
o Mainly in walls of hollow organs and tubes (e.g.
esophagus, blood vessels)
o Regulates the size of organ/tube, moves
contents along
o Tunica media – smooth muscle cells arranged
circularly around the blood vessel
o Vasoconstriction
o Vasodilation
o No striations
o Single nucleus per muscle cell
o Involuntary control
o Can regenerate
Nervous tissue
 Nervous system: brain – spinal cord – nerves
 Main component of nervous system
o Neuron (nerve cells)
o Supporting cells (neuroglia) – nourish, protect
and insulate neurons
 Neurons have the ability to produce and conduct
action potential
 Neurons
o Cell body (soma) contains nucleus
o Dendrites receive information
o Axon conducting or transmitting information
Compendium 2
o
COMPENDIUM THREE: Are you what you eat?
Lecture Notes
Compendium 3 Lecture 1 of 2 – Are you what you eat? P1
Anatomy of the digestive system
Anatomy
 Digestive tract – also called alimentary tract –
continuous tube. Accessory organs – primarily glands,
secrete fluids into tract
o Oral cavity (mouth) with salivary glands
o Pharynx (throat)
o Esophagus
o Stomach
o Small intestine (duodenum, ileum, jejunum) with
liver, gallbladder and pancreas as accessory organs
o Large intestines include Cecil, colon, rectum and
anal canal
o Anus
Functions of the digestive system
 Ingestion: introduction of food into stomach (via
mouth)
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Mastication: chewing. Chemical digestion requires
large surface area so breaking down large particles
mechanically facilitates chemical digestion
 Secretive: lubricate, liquefy, digest (e.g. Mucus:
secreted along entire digestive tract, lubricates food,
coats and protects lining)
 Digestion: Mechanical and chemical digestion of food
into nutrients
 Absorption: Movement of nutrients out of digestive
tract into cells
 Elimination: waste products removed from body;
faeces. Defecation
Histology of the digestive tract
 One large tube from mouth to anus plus the accessory
organs
1. Mucosa: innermost layer, secretes mucus
2. Submucosa: connective tissue layer, contains blood
vessels, nerves etc.
3. Muscularis: 2/3 muscle layers, movement &
secretion
4. Serosa / adventitia: outermost layer, connective
tissue, stability
Peristalsis & segmentation
 Process by which food moves through the gut. Waves
of smooth muscle relaxations and contractions
Peritoneum
 The walls and organs of the abdominal cavity are line
with serous membranes
 Visceral peritoneum: covers organs
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Parietal peritoneum: covers interior surface of body
wall
 Mesenteries: peritoneum (epithelial tissue) which
connects organs together and small intestine to back
body wall
 Routes by which vessels and nerves pass from body
wall to organs
 Greater omentum: connects stomach to transverse
colon
 Lesser omentum: connects stomach to liver and
diaphragm
Oral cavity
 Digestion begins in the oral cavity
 Hard palate: hard bone, anterior
 Soft palate: soft muscle, posterior
 Tongue – taste buds
 Teeth – mechanical digestion of food
 Masticate (chew) food and turn it into a bolus
Teeth
 Two sets of teeth:
o primary, milk teeth (childhood)
o Permanent or secondary adult (32)
o Types: (8) Incisors - cutting, (4)canines – tearing
food, (8)premolars- grinding and (12) molars –
grinding
Oral cavity – salivary glands
 Salivary glands – produce and secrete saliva into the
oral cavity. (3 main – Parotid, Sublingual and
submandibular glands)
 Saliva – protects oral cavity, moistens, lubricates and
digests food
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Amylase – enzyme found in saliva that breaks down
carbohydrates into smaller sugars
 Lysozyme – antibacterial enzyme
Pharynx & Esophagus
 Pharynx: throat – connects oral cavity to the
esophagus. Uvula (soft palate) prevent food/drink from
entering the nasopharynx
o Nasopharynx (behind nose)
o Oropharynx (behind oral cavity)
o Laryngopharynx (behind the larynx)
 Esophagus: tube that connects pharynx to stomach.
25cm long, lies posteriorly to the trachea
o Epiglottis prevents food/drink from entering
trachea
o ends as gastro-esophageal sphincter
Swallowing
 Voluntary phase: tongue pushes bolus to the back of
the oral cavity towards pharynx (oropharynx)
 Pharyngeal phase: soft palate (Uvula) closes off the
nasopharynx. Bolus touches receptors on oropharynx
and swallowing reflex moves bolus down pharynx and
into esophagus. Epiglottis covers trachea
 Esophageal phase: bolus is moved down esophagus
towards stomach by peristalsis
Stomach
 Located in abdomen ‘holding point’ for food
 Food comes from the esophagus and the stomach
mixes it (churns) into chyme (thick liquid)
 Produces mucus, hydrochloric acid, protein digesting
enzymes (pepsin)
 Contains a thick mucus layer that lubricates and
protects epithelial cells on stomach wall from acid pH
2-3
 Openings / sphincters
o Gastroesophageal (cardiac): to esophagus
o Pyloric: to duodenum
 Parts
o Cardiac
o Fundus
o Body
o Pyloric: antrum and canal
 Layers
o Visceral peritoneum or serosa
o Muscularis: three layers
 Outer longitudinal
 Middle circular
 Inner oblique
o Submucosa
o Mucosa – simple columnar epithelium
 Rugae: folds in stomach wall that allows stomach to
stretch after eating
Movements of the stomach
 3 muscular layers enable churning of food. Make
chyme
 Combination of mixing waves (80%) and peristaltic
waves (20%)
 Both esophageal and pyloric sphincters are closed
 Water takes about 1-2 hours to exit (via kidneys and
urethra) after digestion)
 Stomach empties every 4hrs (6-8 after a fatty meal)
Small intestine
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Very long – 6m small diameter
Large surface area for efficient absorption of nutrients
Connected to posterior body wall by mesenteries
Divisions
o Duodenum (first 25cm) beyond the pyloric
sphincter
 Curves around the pancreases. Chyme mixes
with various digestive enzymes. Mucous from
Brunner’s glands neutralize acidic chyme.
Located in epigastric and umbilical regions
o Jejunum 2.5 m
 Large amount of nutrient absorption happens.
Extensive villi. Located in left lumbar and
umbilical region
o Ileum 3.5 m
 Adaptations increase surface area of small intestine
600 fold
o Plicae circulares: circular folds in the wall of the
small intestine
o Villi: finger like folds of epithelium. Contains
capillaries and lacteals
o Microvilli: small extensions on epithelial cell surface
o Lipid – lacteals – lymph. Carbs and proteins –
capillaries – blood
Liver and gall bladder
 Liver – makes bile (100ml per day)
o Filters blood nutrient rich coming from the
intestines (portal system)
o Stores glucose as glycogen and lipids for energy
o Detoxification of drugs and toxins
 Gall bladder – muscular sac, stores and concentrates
bile. Bile enters the duodenum via the common bile
duct, emulsifies fats/lipids
Pancreas
 Produces digestive enzymes. Produces insulin and
glucagon for blood sugar homeostasis
 Lipase – breakdown lipids
 Pancreatic amylase – breakdown carbohydrates
 Trypsin – breakdown proteins
Large intestine
 Absorption of water and NaCl
 Extends from ileocecal junction to anus
 Consists of cecum, colon (ascending, transverse,
descending, sigmoid), rectum, anal canal
 Bacteria / microtubes synthesise vitamin B & K
 18-24hr transit time; chyme  faeces
 1500mL chyme enter the cecum, 90% reabsorbed
yielding 80-150 ml of faeces
 Defecation reflex – triggered by rectal distention
 Goblet cells – mucous
The digestive process
 Digestion: mouth, stomach, small intestine. Breakdown
of food molecules for absorption into circulation
Mechanical: breaks large food particles to smaller
ones. Chemical: breaking of covalent bonds by
digestive enzymes
 Absorption: nutrients from the small intestine, water
from the large intestine. Molecules are moved out of
digestive tract and into circulation for distribution
throughout body (via liver)
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Compendium 3 Lecture 2 of 2 – Are you what you eat? P2
Nutrition and macromolecules
Enzymes
 A protein catalyst that increases the rate at which a
chemical reaction proceeds, without the enzyme being
permanently changed
 Highly specific – active site on an enzyme can only bind
to specific reactant
 Many different enzymes needed in the body for
different chemical reactions
 Often named by adding ‘ASE’ as a suffix to their
reactant
Nutrients
 Chemical taken into body to
o Produce energy
o Provide building blocks to build other molecules
 6 classes: carbohydrates, proteins, lipids, vitamins,
minerals and water
 Carbohydrates, proteins and lipids are major organic
nutrients (organic = contains carbon
 Need large amounts of vitamins and minerals
o Taken into body without being digested
 Essential nutrients – are chemicals that must be taken
into the body because we can’t make them ourselves
o Includes some amino acids/fatty acids/carbs, water,
most vitamins and minerals
 Six major classes of nutrients:
o Carbohydrates – (sugars from plants and
vegetables)
o Lipids – animal products and oils
o Proteins – meat, fish, poultry
o Vitamins – organic molecules – plants and animals
o Minerals – in organic (iron)
o Water
 Recommended amounts
o Carbohydrates (45-65%)
o Lipids (20-35%)
o Proteins (10-35%)
o Consider personal needs
o Consider source
Carbohydrates
 Most come from plants (exception lactose from milk)
 Contains C, H and O =CHO
 Sugars e.g. glucose
 Don’t need to know the molecular structure
 Very large molecules – made up of many smaller
building blocks
Mono & disaccharides
 Monosaccharides
o glucose (blood sugar)
o fructose (fruit sugar)
o galactose (milk sugar)
 Disaccharides
o Sucrose (table sugar) glucose + fructose
o Lactose (milk) glucose + galactose
o Maltose – glucose + glucose
Polysaccharides
 Long chain of monosaccharides 3000+
 Glycogen
o Animal polysaccharide
o
Glucose molecules stored in humans in liver and
muscle
 Starch and cellulose
o Plant polysaccharides
o Humans break down starch
 Energy
o Human can’t break down cellulose – dietary fibre
Carbohydrate absorption
 Polysaccharide chain e.g. glycogen. Digested by saliva
in oral cavity & pancreatic amylase in duodenum
 Disaccharide chain. E.g. sucrose digested by sucrase in
the intestine
 Monosaccharide chain e.g. glucose absorbed into
blood via villi / microvilli in intestine. Transported to
liver via hepatic portal vein
Carbohydrates uses in the body
 Glucose  produce ATP energy
 Energy – warmth, movement, brain activity, muscle
contraction etc.
 Excess glucose  glycogen and stored in muscle and
liver cells
 Excess beyond storage is converted to fat
 Sugars also become part of DNA, RNA and ATP
glycoproteins, glycolipids (essential for cell
membranes)
Proteins
 Contain C, H, O, N and sometimes sulfur
 Amino acids are the basic building blocks
 Each amino acid has an amine group (NH2) and
carboxyl group and a hydrogen and a side group
 Side group is what is different between amino acids
 Amino acids link together to form peptides and
proteins
 Amino acids are not stored in the body
 Essential amino acids, can’t be produced by body so
must be obtained from the diet
 Non-essential amino acids are still required by our
body, but these we can synthesise from essential
amino acids
 Functions of proteins: regulate body function e.g.
o Globular proteins
o Structural – muscle proteins
o Cell membrane transport
o Enzymes
o Hormones
o Antibodies
 Complete protein – food that contains enough of all 9
essentials amino acids e.g. meat, fish, poultry, milk,
cheese, eggs
 Incomplete protein e.g. leafy green vegetables, grains,
legumes
Protein absorption
 Protein (long chain of amino acids) digested by pepsin
in stomach
 Polypeptides digested by trypsin in duodenum
Lipids
 Composed mostly of carbon, hydrogen, oxygen and
sometimes nitrogen and phosphorus
o Lower ratio of O to C than carbs
o Lipids / fats ingested are broken down to release
energy
9
Triglycerides make up 95% of fats in body
 Glycerol and fatty acids
 Fatty acids – can be different lengths
 Saturation: how many H atoms on each
chain
 Saturated – animals fats e.g. beef, pork,
milk
 Unsaturated – plant sources – contains
one or more double bonds in the
carbon chain so there is less H atoms.
More relaxed structure (liquid at RT)
 Trans fats – unsaturated fats that are
artificially altered
Lipid absorption
 Lipid (triglycerides) digestion begins in the duodenum
 Bile from the gall bladder emulsifies lipids
 Lipase from the pancreas causes further breakdown
 Short chain fatty acids (monoglycerides) are absorbed
Uses of lipids in the body
 Cholesterol: found in liver and egg yolks or
manufactured by body. Component of plasma
membranes ,modified to form bile salts
 Phospholipids: major components of plasma
membranes, myelin sheath, part of bile
 Eicosanoids: derived from fatty acids. Involved in
inflammation, blood clotting, tissue repair, smooth
muscle contraction
Water absorption
 Approximately 9L of water enters the digestive tract
each day
 99% of water entering the intestine is absorbed
 Water can move across the intestinal wall in either
direction if required
 Ions: sodium, potassium, calcium, magnesium,
phosphate are actively transported
Vitamins
 Organic molecules in very small quantities in food
 Essential for normal metabolism and can’t be produced
by the body
 No one food provides all necessary vitamins, some are
produced by intestinal bacterial
 Vitamins can be fat soluble, or water soluble – consider
route of admission
 Too much
o Vt C- stomach inflammation; diarrhea
o Vit A – toxic during pregnancy
o Vit D – alter calcium metabolism
 Vitamin deficiencies
o Vit D – rickets
o Vit C – scurvy
o Vit B beriberi
Minerals
 Inorganic nutrients
 Major minerals: calcium, magnesium, sodium and
potassium
 Trace minerals: selenium, zinc, copper
 Components of co-enzymes, some vitamins,
haemoglobin, organic molecules
 Functions
o Membrane potential and action potentials
o
o Add mechanical strength to bones and teeth
 Available from both plant and animals based foods
 Mineral deficiencies
o Iron – anaemia
o Potassium – muscle weakness, abnormal heart
function
o Iodine – goitre
COMPENDIUM FOUR: Why do we breathe?
Compendium Lecture 1 of 4 – Why do we breathe? P1
Anatomy of the respiratory system
Functions of the respiratory system
 Respiration
o Ventilation – movement of air in and out of lungs
o External respiration – gaseous exchange between
lungs and blood
o Respiratory gas transport – through blood to the
whole body
o Internal respiration (tissue level) – gaseous
exchange between blood and tissues
 Blood pH regulation
o How acidic or alkaline a medium is (0 is highly
acidic, 7 neutral, 14 highly alkaline)
o Blood maintains a specific pH between 7.35 and
7.45
o If there is an increase of CO2 in the blood it’s going
to make the blood more acidic  CO2 needs to be
removed
 Sound production
o As air passes through the vocal cords in the larynx
of the tract, the sound can be modified in pitch – on
the vocal folds
 Olfaction
o Specialized cells in the nasal cavity which are
sensitive to smell
 Protection
o Protects us from bacteria and spores and other
harmful substances in the air
Organisation of the respiratory system
 Nares – nostrils
 Nasal cavity
 Pharynx
 Larynx
 Trachea
 Bronchi – primary, secondary, tertiary
 Bronchioles – terminal, respiratory
 Alveolar duct
 Alveoli
Divisions of respiratory system
 Structural classification
o Upper respiratory tract: nose, nasal cavity, pharynx
o Lower respiratory tract: larynx, trachea, bronchi,
bronchioles and alveoli of the lungs
 Functional classification
o Conducting zone (no gaseous exchange occurring):
from nose to terminal bronchioles
o Respiratory zone (gaseous exchange takes place):
respiratory bronchioles, alveolar duct and alveoli
Nares and nasal cavity
 External nose
 Vestibules : area between nares
10
Nasal cavity
o Nares to choana
o Nares
o Vestibule
o Septum
o Floor of nasal cavity
 Hard palate soft palate, uvula
o Conchae and meatuses
 Superior, middle and inferior conchae (ridges)
 Superior, middle and inferior meatuses
(depressions)
 Creates turbulence in air
o Sinuses
 Paranasal sinuses and tear ducts
 Empty areas in the bones which makes your
skull lighter and causes resonances as you
speak
 Main function: to purify the air, the humidify the air,
and to bring the air in the body at a normal
temperature
Functions of nasal cavity
 Passageway for air
 Hair – filters coarse particles from the inspired air
 Mucus – traps dust, bacteria and other debris from the
inspired air, humidifies air
 Cilia – create gentle current by beating moving
contaminated mucus towards throat to be swallowed
 Lysozyme – kills bacteria
 Rich capillary network – maintain temperature of
inhaled and exhaled air
 Conchae and meatuses – increase mucosal surface,
create turbulence facilitating above functions
 Olfaction – olfactory epithelium containing olfactory
receptors
 Sinuses, nasal cavity – resonating chambers, lighten
skull
Pharynx
 Tube like structure from
 Common passage for food and air
 Divided into 3 regions
o Nasopharynx
 Posterior to nasal cavity
 Choana to uvula
 Eustachian tube opening
 Pharyngeal tonsils
o Oropharynx
 Posterior to oral cavity
 Uvula to epiglottis/hyoid bone
 Common passage for air and food
 Palatine and lingual tonsils
o Laryngopharynx
 Posterior to epiglottis
 Epiglottis/hyoid bone to larynx/esophagus
Larynx
 Voice box
 Passageway of air
 Superior: pharynx
 Inferior: trachea
 9 cartilages
o 3 unpaired
 Thyroid (Adam’s apple)

 Cricoid
 Epiglottis
o 3 are paired (6)
 Arytenoid
 Corniculate
 Cuneiform
o Ligaments extend from arytenoids to thyroid
cartilage
 True vocal cords of vocal folds
 Vestibular folds or false vocal folds
 Opening between is glottis
Function of larynx
 Maintains an open passageway for air movement
(cartilages)
 Directs food into the oesophagus away from the
respiratory tract
 Sound production via vocal folds

Traps debris from entering lungs
Trachea
 From larynx till carina (special cartilage) – really
sensitive to any debris or dust
 Tough but flexible membranous tube, approximately
10-12 cm long and 2 cm in diameter
 Anterior oesophagus, passes through the mediastinum
 Cartilages dense regular CT and smooth muscle
 15-20 C-shaped hyaline cartilage rings with smooth
muscle in between
 Smooth muscle: it allows flexibility between esophagus
and trachea for peristalsis
 Presence of trachealis muscle posteriorly
 Divides into two main bronchi at carina
 Mucosa of carina is very sensitive, cough reflex
Function of trachea
 Cartilage keeps the airway open
 Trachealis muscle facilitates ease of peristaltic
movements in esophagus
 Contraction of trachealis muscle causes expired air to
rush out with greater force (puffing)
 Cleansing of air breathed in
 Sensitive nature of carina triggers coughing to expel
foreign particles
Tracheobronchial tree
 Primary (main) bronchi
 Secondary (lobar) bronchi – 2 in left and 3 in right lung
 Tertiary (segmental) bronchi – 10 on each side
 Bronchioles (<1 mm diameter)
 Terminal bronchioles (<0.5 mm in diameter
Progressive changes in tracheobronchial tree
 Decrease in passageway diameter
 Decrease in cartilage – rings replaced by irregular
cartilage plates and finally by elastic fibres in
bronchioles

Increase in smooth muscle – from in between cartilage
rings to complete layer of circular smooth muscle
(bronchioles)
 Changes in epithelium – from pseudostratified ciliated
columnar to simple ciliated cuboidal epithelium
Respiratory zone
 The difference between respiratory bronchiole and the
terminal bronchiole is that you have occasional alveoli
11
on the respiratory bronchial – which leads to alveoli
ducts which opens into alveoli sac
 Respiratory bronchioles
o Very few alveoli
 Alveolar ducts
o Have more alveoli, end in alveolar sacs
 Alveolar sac
o Chambers connected to two or more alveoli
 Alveoli
o Small bag like structures, richly supplied by blood
capillaries, contains elastic fibres, 300-500 million
alveoli, large surface area for gas exchange
Lungs
 Located in the thoracic cavity, one on either side of the
mediastinum
 Cone shaped, base on diaphragm, apex
 Costal, medial and diaphragmic surfaces
 Cardiac notch medially on left lung
 Right lung has three lobes (superior, middle and
inferior) separated by two fissures (horizontal and
oblique)
 Left lung has 2 lobes (superior and inferior), separated
by one (oblique) fissure
 Hilum – indentation on medal surface, entry/exit point
for blood vessels, nerves, lymphatic vessels and
bronchi
Lungs in segments
 Bronchopulmonary segments – 10 in right and 8/9 in
left lung
 Lobules
 Lobules are separated by partially by connective tissues
 25 orders / levels of branching from trachea to alveoli
duct
 Primary bronchi
o (main) bronchi, supply each lung
 Secondary bronchi
o (lobar), bronchi, supply the lobes
 Tertiary bronchi
o (segmental), bronchi, supply bronchopulmonary
segments
Pleura/Pleural membrane
 Double-layered serous membrane
 Parietal pleura – superficial, lines inner wall of thoracic
cavity (attached to rib cage)
 Visceral pleura – deep, covers the lungs (attached to
lung)
 In between the 2 pleura is the pleural cavity
 In the pleural cavity there is pleural fluid, which is
lubricating fluid secreted by pleura, fills pleural cavity
 Reduces friction cases two membranes to adhere,
protects and reduces impact of force
Respiratory system epithelium
 Epithelium changes along respiratory track to
accommodate the specific function of the structure
o Vestibule – keratinised stratified squamous
epithelium
o Nasal cavity – pseudostratified ciliated columnar
epithelium
o Nasopharynx – pseudo stratified ciliated columnar
epithelium
o Oropharynx – stratified squamous epithelium
o
o
Laryngopharynx – stratified squamous epithelium
Trachea – pseudostratified ciliated columnar
epithelium (with goblet cells)
 Between trachea and alveoli, epithelium gradually
changes from PSCC (bronchi) to ciliated simple
columnar (larger bronchioles) to ciliated simple
cuboidal (terminal bronchioles) to simple cuboidal
(respiratory bronchioles) to simple squamous (alveoli)
o Alveoli – simple squamous epithelium
Compendium 4 lecture 2 of 4 – Why do we breathe? P2
Gas exchange
Alveolus (alveoli, pl)
 Alveoli – cup shaped pouches, 300 - 500 million
 Alveolar sac – contains 2 or more alveoli sharing a
common opening
 Lined by simple squamous epithelium and supported
by thin elastic basement membrane
 Two types of epithelial cells:
o Type 1 pneumocytes – simple squamous epithelial
cells, site of gas exchange
o Type 2 pneumocytes – simple cuboidal cells,
secrete alveolar fluid and surfactant
 Dust cells – alveoli macrophages, remove fine dust and
debris from alveolar spaces
Respiratory membrane
 Very thin, 0.5 micrometres
 Alveoli increase surface area for gas exchange (70m^2)
 Gas exchange through simple diffusion
 Consists of 3 layers
o Alveolar epithelium (type 1 and type 2
pneumocytes)
o Fused alveolar and capillary basement membrane
o Capillary endothelium
 Red blood cells, macrophages
 Alveolar fluid lining the inside of the alveolus – mixed
the surfactant which doesn’t allow the alveolus to
collapse
Characteristics of a respiratory membrane
 Thickness of the respiratory membrane
o Thinner membrane increases the rate of movement
of gas
 Surface area
o Higher surface area the more gas exchange
 Diffusion coefficient
o Diffusion coefficient – how easily a gas can diffuse
in and out of a liquid or tissue
o Relative number (02 is 4, whereas Co2 has 20)
 Partial pressure
o Pressure exerted by a particular gas would be its
partial pressure
o The gas moves from the side with the higher Pp to
the side with the lower Pp (partial pressure)
 Moist membranes
o Gases dissolve in the fluid helping them to diffuse
o Alveolar fluid, plasma
Gas transport and exchange
 Gases does not move as gas bubbles
 O2
o Travels in blood
 Red blood cells (haemoglobin) – 98.5%
12
 Dissolved in blood plasma (1.5%)
o Exchange in body
 From alveoli to blood- external respiration
 From blood to tissues – internal respiration
 CO2
o Travels in blood
 HCO3 dissolved in plasma (70%)
 CO2 dissolved in plasma (7%)
 Bound to haemoglobin (23%)
o Exchange in body
 From blood to alveoli – external respiration
 From tissue to blood – internal respiration
4 stages of respiration
1. Pulmonary ventilation
2. External respiration
3. Internal respiration
4. ???
Pulmonary ventilation
 Breathing in and out/inhalation and exhalation
 Prevents build-up of CO2 in blood, supply O2 to tissues
 Involves partial pressure changes, muscle movement,
respiratory rates and volumes
 As you breathe in air it gets humified – it drops the
partial pressure from 160-104
 Residual volume of air in your lungs – increases Co2
levels
External respiration
 Gas exchange between alveoli and the capillaries
 The blood is coming through the pulmonary artery,
which contains a de oxygenated blood from the
different parts of the body
 There is a partial pressure gradient
 Exchanges keeps happening until the partial pressure
equalises
 Gas exchange between alveolar air spaces and alveolar
capillaries across respiratory membrane
 Partial pressure gradient for O2 and CO2 dictates the
direction of movement
 Gases move from higher partial pressure to lower
partial pressure
Internal respiration
 Partial pressure of oxygen in tissue is 20
 Gas exchange between tissue capillaries and tissues
across capillary walls
 Partial pressure gradient for O2 and CO2 dictates the
direction of movement
 Gases move from higher partial pressure to lower
partial pressure
Compendium 4 Lecture 3 of 4 – Why do we breathe? P3
Ventilation
Pulmonary ventilation
 Process of moving air into and out of the lungs
 Structures involved in ventilation
o Sternum
o Rubs
o Lungs
o Muscles – intercostal muscles, sternocleidomastoid,
scalene, pectoralis minor
Muscles involved in breathing
 Quiet breathing
o Inhalation
 Diaphragm
 External intercostal muscles
o Exhalation
 Relaxation if inspiratory muscles
 Elastic recoil of lungs, surface tension
 (no muscles really involved)
 Active Breathing
o Inhalation
 Diaphragm
 External intercostal muscles
 Sternocleidomastoid
 Pectoralis minor
 Scalene muscle
o Exhalation
 Relaxation of inspiratory muscles
 Elastic recoil of lungs, surface tension
 Internal intercostal muscles
 Abdominal muscles
Basic facts
 Boyle’s law
o Volume is inversely proportional to pressure
 Partial pressure gradient
o Air moves from areas of high pressure to areas of
low pressure
 Barometric air pressure (PB)
o Atmospheric air pressure outside the body
 Intra-alveolar pressure (Palv)
o Pressure inside the alveoli
 Barometric pressure is normally 760 mm Hg so will be
equal to 0mm Hg
o If Palv is 759mm Hg, it will be equal to -1mm Hg
o If Palv is 761 mm Hg, it will be equal to 1mm Hg
Process of ventilation
 End of respiration
o PB = Palv
o No flow of air
 Inspiration
o PB > Palv
o Diaphragm contracts ,moves inferiorly and flattens
o External intercostal muscles contract, elevating rib
cage and sternum
o Result:
 Lung volume increase
 Intra alveolar pressure decreases
 Air rushes in in equalise pressure
 End of inspiration
o PB = Palv
o No flow of air
 Forceful inhalation breathing muscles
o More muscles
o Chest muscles
o They elevate the ribcage much further high up
increasing the volume more
 Forceful exhalation breathing muscles
o Intercostal muscles – layer of muscles between ribs
– Press the ribcage further down, and pushes
diaphragm further up
Changing alveolar volume
 Intrapleural pressure = pressure in the pleural cavity
 Forces which promote alveoli recoil:
o Alveoli are covered in fine elastic fibres
13
Fluid which coats alveoli on the inside
 Surfactant (breaks up surface tension and
doesn’t allow the alveoli to completely
collapse)
 Forces which promote lungs expansion:
o Intra-pleural pressure < intra-alveolar pressure
 Visceral pleura adhering to parietal pleura
Compendium 4 lecture 4 of 4 -Why do we breathe? P2
Respiratory volumes and capacitates
Pulmonary volumes
 Once we have taken a tidal breath in, we can forcefully
inhale more air =
 Tidal volume of 500 mL (the amount of air inspired or
expired with each breath
 Inspiratory reserve volume: the amount of air that can
be inspired forcefully after inspiration of the tidal
volume

Expiratory reserve volume: the amount of air that can
be forcefully expired after expiration of the tidal
volume
 Residual volume: the volume of air remaining in the
respiratory passages and lungs after the most forceful
expiration
Pulmonary capacities
 The sum of two or more pulmonary volumes
 Inspirational capacity: the amount of air a person can
inspire maximally after normal expiation (tidal volume
+ inspiratory reserve volume)
 Functional residual capacity: the amount of air
remaining in the lungs at the end of a normal
expiration (expiratory reserve volume + residual
volume)
 Vital capacity: the maximum volume that can be
expelled from the respiratory tract after a maximum
inspiration
 Total lung capacity: inspiratory reserve volume +
expiratory reserve volume + tidal volume
Definitions
 Respiratory rate: number of breaths taken per minute
 Minute ventilation: the total amount of air moved into
and out of the respiratory system each minute (tidal
volume X respiratory rate)
o E.g. 500ml X 12 breaths per minute = 6000ml per
minute)
 Anatomic dead space: space formed by nasal cavity,
pharynx, larynx, trachea, bronchi, bronchioles and
terminal bronchioles
 Alveolar ventilation: volume of air available for gas
exchange per minute
 Forced vital capacity (FVC): maximal volume of air that
can be forcefully expired as fast as possible after a
deep breath in
 Forced expiratory volume in 1 second (FEV1sec): the
volume of air expired in the first second of the test
 Forced expiratory volume 1% (FEV1%): FEV1sec expressed
as a percentage of the FVC
Lung function
 Diagnose and monitor diseases of lungs e.g. asthma,
chronic obstructive pulmonary diseases
 Dynamic testing
o Lung volume measured in relation to time
o
o Dependant on rate of flow of air
o Usually determined during repetitive breathing
o Essential for diagnosis of obstructive lung disease
 Static testing
o Independent of rate of air flow
o Usually determined during one maximal inspiration
and or expiration
o The following 5 static lung volumes can be
measured:
 VT (tidal volume)
 IRV (inspiratory reserve volume)
 ERV (expiratory reserve volume)
 IC (inspiratory capacity)
 VC (vital capacity)
 Vitalogram
 Spirometer
Obstructive vs Restrictive
 Obstructive
o FVC: = normal
o FEV1 sec <<< normal
o FEV1%: <<< normal
o FEV1sec is an indicator of an obstructed airway
o Lung volume normal, airways are narrower
o E.g. asthma, bronchitis, chronic obstructive
pulmonary disorder (COPD)
 Restrictive
o FVC: <<< normal
o FEV1sec: <normal
o FEV1%: = normal
o FVC is an indicator of a restricted airway
o Overall lung volume decreases
o E.g. pulmonary fibrosis, pneumonia and pulmonary
edema, emphysema
Exercise and ventilation
 Ventilation increases abruptly
o Onset of exercise
o Movement of limbs has a strong influence
 Ventilation increases gradually
 Exercise adaptations
o Slight increase in vital capacity
o Slight decrease in residual volume
o At maximal exercise, tidal volume and minute
ventilation increases
COMPENDIUM FIVE: How do we fuel our
body?
Lecture
Compendium 5 – Lecture 1 of 4 How do we fuel our body?
P1 Transport across the cell membrane
Plasma membrane
 Forms a complete boundary around the cell
 Composed of phospholipids, proteins and cholesterol
 The bi-molecular layer of the phospholipid molecules
forms the basic structure
 Cholesterol molecules are inserted between the
phospholipid molecules are regular intervals
 Also incorporates both integral and peripheral proteins
The plasma membrane: composition
 Lipid bilayer serves as a highly impermeable barrier to
most “charged (polar)” and “non-lipid soluble
substances”
14
Integral proteins acting as “pores, channels” or
“carriers” to allow these substances to cross the
membrane
 Selectively permeable
o Solubility in lipids
o Driving forces (up or down a gradient)
o Molecular size
 Transport can either be active or passive
 Water – soluble substances require specialized
transmembrane proteins to function as channels or
carriers
Transport across the membrane
 3 types of passive transport
o Diffusion through the lipid bilayer
o Diffusion through ion channels
o Facilitated diffusion using a carrier
 Active transport requires cellular energy (ATP)
Diffusion THROUGH the lipid bilayer
 Lipid-soluble substances, e.g. respiratory gases, lipids,
small alcohols and urea can diffuse across the lipid
bilayer
 A concentration gradient is using the driving force
Diffusion ACROSS the lipid bilayer
 Water-soluble substances e.g. ions, small sugars, amino
acids and water need integral membrane proteins to
move across the cell membrane
o Small ions (channels)
o Water (channels)
o Sugars and amino acids (facilitated diffusion)
 Gradient is driving force
Facilitated diffusion
 A solute binds to a specific transporter on one side of
the membrane and is released on the other side
 Solutes that move in this way include glucose (out of
the cell) and fructose (into the cell)
 Rate of movement depends on
o How steep of conc. Gradient
o Number of transporter proteins in the membrane
“gated” Protein channels
 Some membrane proteins are ion channels
 An electrochemical gradient is often the driving force
 ion channels are selective and specific
 some channels formed by train property and are
continually open, but others are only open transiently
– said to be gated
 Transport much faster a than facilitated diffusion
Active transport
 Active transport is an energy requiring process that
moves solutes against a concentration gradient
 In primary active transport energy is derived directly
from ATP
 In secondary active transport energy is derived
indirectly from ATP
Primary Active transport
 The most common primary active transport
mechanism is the sodium and potassium iron pump
o Requires 40% of cellular ATP
o All cells have thousands of them
o maintained low concentration of sodium and a
higher concentration of potassium in the cytosol
o operates continually

Secondary Active transport
 The energy is stored in sodium or hydrogen
concentration gradient which is used to drive other
substance against their own concentration gradients
 plasma membranes contained several antiporters and
symporters powered by the sodium ion gradient
Membrane transport of complex molecules
 Exocytosis:
o movement of large molecules out of the cell
o occurs in secretory cells
o secretion in vesicles which are membrane packets
o neurotransmitter secretion at the synapse
 endocytosis:
o movement of large molecules in particles into the
cell
 Pinocytosis: engulfing small particle and fluids
 Phagocytosis: engulfing large particles
 Receptor-mediated endocytosis: the
movement of specific substances into the cell
involving the caveolae regions of the cell
membrane
Compendium 5 - Lecture 2 of 4 How do we fuel our body?
P2 The movement of water (osmosis)
The plasma membrane: composition
 Water molecules penetrate the membrane by diffusion
through the lipid bilayer or through aquaporins
(transmembrane proteins) that function as water
channels
 The movement of water is called “osmosis” which is
defined as the “movement of water from a low solute
concentration to a high solute concentration across a
semi-permeable membrane”
Osmosis: the driving forces
 When explaining the driving forces behind water
movement we never talk about water concentration,
instead we refer to the concentration of solutes
dissolved in it
 This is because water is the solvent for all solutes and is
present at a very high concentration: 56 molar
 This means that when solutes are dissolved in water,
its concentration changes very little
 When a solute dissolves in water, the solution displays
an “osmotic pressure” or “drawing power” to
encourage water to move towards it
 Therefore where possible, water always moves to the
solution with the highest osmotic pressure (highest
solute concentration)
 Hence the definition of osmosis
Osmosis
 Osmosis is the net movement of water through a
selectively permeable membrane
 Osmosis occurs only when the membrane is permeable
to water but not to certain solutes
 The osmotic pressure that a solute exerts is
proportional to the number of “osmotically-active
particles” in solution
 The osmotic pressure of a solution is proportional to
the concentration of the solute particles that cannot
cross the membrane
Tonicity
15
Tonicity is a measure of a solution’s ability to change
the volume of cells by altering their water content
 In an isotonic solution – no net movement of water so
cells maintain their normal shape
 In a hypotonic solution – cells gain water and are in
danger of swelling/bursting
 In a hypertonic solution – cells lose water and are in
danger of shrinking and becoming dehydrated
 There are important medical uses of isotonic,
hypotonic and hypertonic solutions
 Tonicity can be best demonstrated with red blood cells
when they are placed in different saline solutions
o Isotonic solution – red blood cells maintain their
normal shape
o Hypotonic solution – red blood cells undergo
haemolysis
o Hypertonic solution – red blood cells undergo
crenation
Compendium 5 – Lecture 3 of 4 How do we fuel our body?
P3 Glycolysis
Introduction
 3 major destinations for the nutrients we eat:
o Energy
o Structural or functional molecules
o Storage compounds
 Most energy is derived from the oxidation of CHO, fat
& protein.
o About 60-70% of the energy released is lost as heat
o Remainder is stored as chemical energy (ATP)
Metabolic Reactions
 Metabolism: all chemical reactions in the body
 Catabolism: chemical reactions that break down
complex organic molecules
 Anabolism: chemical reactions that build-up simple
molecules into complex molecules
 All molecules have energy stored in the bonds between
their atoms
 Chemical reactions depend on transfer of small
amounts of energy from one molecule to another
 This transfer is usually performed by ATP
ATP
 A molecule for the temporary storage of energy
 3 phosphate groups attached to an adenine base and a
5C sugar (ribose)
 ATP is used for muscle contraction, active transport,
movement of structures within cells etc.
 Large amounts of energy are released when ther
terminal phosphate bond is hydrolysed (broken)
Stage in energy generation
 First stage
o Large molecules  smaller units:
 Proteins  peptides and amino acids
 Fats  glycerol and fatty acids
 Polysaccs  simple sugars
 Second stage
o Smaller units are degraded to a few simple key
compounds that play a central role in metabolism
 Third stage
o Citric acid (Krebs) cycle and
o Oxidative phosphorylation
Carbohydrate metabolism


During digestion, polysaccharides and disaccharides
are converted to monosaccharides
o CHO metabolism is primarily concerned with
glucose metabolism
 Glucose is catabolised in three pathways
o Glycolysis
o Krebs cycle
o The electron transport chain & oxidative
phosphorylation
Cellular Respiration
 Metabolic pathways synthesise ATP
o Anaerobic: ATP production in absence of O2:
glycolysis
o Aerobic: ATP production using O2: Oxidative
Phosphorylation
 4 steps
Anaerobic
o Glycolysis
o Formation of acetyl CoA as a transitional stem
Aerobic
o Krebs cycle
o Electron transport chain
Glycolysis
 Initial step  activate glucose
 Later in glycolysis  4ATP liberated as energy
 Phase 1: Sugar activation
o Two ATP molecules are used to activate glucose
(fructose-1, 6-bisphophate)
 Phase 2: Sugar cleavage
o 6C sugar is split into two 3C sugars
o Each 3C has a phosphate group
o Inorganic phosphate groups are attached to each
oxidised sugar fragment
 Phase 3: Oxidation & ATP formation
o The phosphates are split from the sugar and
captured by ADP to form 4 ATP molecules
o The remaining 3C sugars are pyruvic acid
o The final products
 2 pyruvic acid molecules
 2 NADH and H molecules
 A net gain of 2 ATP molecules
o If O2 is available, pyruvic acid prepares to enter the
Krebs’s Cycle
o If o2 is not available, PA accepts H2 from NADH2 to
form lactic acid
Glycolysis: Fate of Pyruvic acid
 The fate of pyruvic acid depends on the availability of
O2
 When O2 is not available
o The pyruvic acid is reduced to lactic acid
o Lactic acid rapidly diffuses out of cell into the blood
o Liver cells remove lactic acid from blood & convert
it back to pyruvic acid
 When O2 is available
o Pyruvic acid proceeds to the Krebs cycle in the
mitochondrion
Compendium 5 – Lecture 4 of 4 How do we fuel our body?
P4 Kreb’s Cycle & Oxidative Phosphorylation
Formation of Acetyl Coenzyme A
 Pyruvic acid enters the mitochondria & undergoes
decarboxylation (removes Co2)
16
Pyruvate dehydrogenase converts 3C pyruvic acid to 2C
acetyl group plus Co2
 2C acetyl group is attached to coenzyme A to form
acetyl coenzyme A which enter Krebs cycle
o Coenzyme A is derived from Vitamin B
o It behaves as a “carrier or taxi” for the 2C acetyl
group
Krebs cycle
 The Krebs cycle is also called the citric acid cycle, or the
tricarboxylic acid (TCA) cycle
 It is a series of biochemical reactions that occur in the
matrix of mitochondria
 The 2C component of acetyl CoA is pulled apart bit-bybit to release Co2 and H

The H are sent to the Electron Transport Chain (ETC) as
NADH and FADH to be converted into energy
The Krebs (Citric acid, TCA) cycle
 Krebs cycle is a series of reaction which occur in the
matrix of mitochondria
o Acetyl CoA (2C) enters the cycle & combines with a
4C compound to form citric acid
 Potential energy in the chemical bonds is released
step-by-step to reduce the coenzymes which
temporarily store this energy
 NAD+ and FAD+ are H2 carriers
 (2C) acetyl CoA + (4C) oxalo-acetic acid  (6C) citric
acid
 A series of reactions involving the elimination of 2C &
4O as 2CO2, and the removal of hydrogen occurs
 6C citric acid becomes 4C oxalo-acetic acid to complete
the cyclic pathway
The Krebs cycle summary
 Each acetyl CoA molecule that enters the Krebs cycle
produces:
o 2 molecules of Co2
o 3 molecules of NADH2
o 1 molecule of ATP
o 1 molecule of FADH2
 Each glucose produced 2 acetyl CoA molecules
 Total yield = (above produces) x 2
Electron transport chain
 The ETS is located in the mitochondria
 Integral membrane proteins (cytochromes) form a
chain which is located in the inner mitochondrial
membrane
 Each cytochrome picks up electrons and passes them
on to the next in the chain
 Small amounts of energy are released as this occurs
 This energy is used to form ATP
 Oxidative phosphorylation produces the vast majority
of ATP in cell
The Electron transport chain
 The ETC is a series of cytochromes located in the inner
mitochondrial membranes
 Hydrogens delivered to the chain are split into protons
and electrons
 As electrons are passed through the chain, there is a
stepwise release of energy from the electrons for the
generation of ATP
Steps in the Electron transport chain


Proteins of the ETC are clustered into 3 complexes that
each act as proton pumps (move H+ into the inner
membrane space)
 The electrons are shuttled from one cytochrome
complex to the next
 Final complex passes its electrons(2H+) to a half of O2
molecule to form water H20
 The build-up of H+ outside the inner membrane
creates a positive charge
o Electrochemical gradient of potential energy
 ATP synthase enzyme within H+ channel uses this
potential energy to form ATP from ADP and iP
Electron transport chain
 H+ ions are transported from matrix into the space
between the inner and outer membranes
 This ensures a high concentration of H+ is established
between the inner and outer membranes
 ATP is formed as H+ diffuse through special ATP
synthase channels back to the matrix
Summary of Aerobic Cellular Respiration
 Glucose (+O2) is broken down into CO2 + H2O + energy
used to form ATP:
o 2 ATPs are formed during glycolysis
o 2 NADH2 are formed during glycolysis
o 2 NADH2 are formed when converting pyruvate to
acetyl CoA
o 2ATPs are formed directly during Krebs cycle
o 6 NADH2 are formed during Krebs Cycle
o 2 FADH2 are formed during Krebs cycle
 For each NADH2 the proton gradient generates 3 ATP:
o 10 NADH2, generates 10x3 ATP = 30 ATP
 For each FADH2 the proton gradient generates 2 ATP:
o 2 FADH2 generates 2x2 ATP = 4 ATP
 From each glucose molecule 4 ATPS are generated
o Oxidative phosphorylation generates 36-38 ATPs
from one glucose molecule
 2x NADH2 formed during glycolysis produce less ATP
via OP
 The complete oxidation of glucose can be represented
as follows:
o C6H12O6  36 or 38 ATP + 6CO2 +6H2O
 Benefit: H2 obtained from a wide variety organic
molecules  funnelled  common energy carrier, ATP
 Involves a complex series of reactions in the
mitochondrion
 Oxidative phosphorylation produces the vast majority
of ATP in cell
COMPENDIUM SIX: How do things get around
the body?
Lecture
Compendium 6 – Lecture 1 of 2 How do things get around
the body? P1 Cardiovascular system – the heart
The cardiovascular system
 Heart, blood vessels, capillary beds and blood
 Transports fluids, nutrients, waste products, gases and
hormones throughout the body
 Exchange materials between blood, cells and
extracellular fluid
 Plays a role in the immune response, blood pressure
and the regulation of body temperature
17
The heart has to
 Generate blood pressure – moves blood through
vessels
 Route blood: separates pulmonary (lung) and
systematic (body) circulations
 Ensure a one-way blood flow
 Regulate blood supply – nervous or endocrine system
 60-100 beats per minute
 Pumps around 5.2L of blood per minute (7200L per
day)
The heart – location
 Located in the thoracic cavity in mediastinum
 Size of a closed fist
 Shape - inverted pyramid
o Base: flat part at opposite end of cone (superior)
o Apex: blunt rounded point of cone (inferior)
The heart – pericardium
 Fibrous pericardium: tough fibrous outer layer,
prevents over distention; acts as anchor
 Serous pericardium: thin, transparent, inner layer,
simple squamous epithelium
o Parietal pericardium: lines the fibrous outer layer
o Visceral pericardium: covers heart surface
 The two are continuous and have a pericardial cavity
between them filled with pericardial fluid
 The heart is inside its own fluid sac
Heart wall
 Three layers of tissue
o Epicardium: serous membrane; smooth outer
surface of heart (visceral pericardium) – there are
loose connective tissues called epicardium fat
o Myocardium: middle layer composed of cardiac
muscle cells – contractibility (majority of the heart)
o Endocardium: smooth inner surface of heart
chambers
 Pectinate muscles: muscular ridges in auricles and right
atrial wall – run parallel to each other
 Trabeculae carnae: muscular ridges and columns on
inside walls of ventricles (meaty columns)
The heart – 2 pumps in 1
 It is feeding two different circulations – lung and body
 Right side of heart is pumping blood to lungs and left
side of lungs is pumping from lungs to body
The heart – chambers
 Right atrium: three major openings to receive blood
returning from the body
 Left atrium: four openings that receive blood from
pulmonary veins
 Atrioventricular canals: opening between atria and
respective ventricles
 Right ventricle: opens to pulmonary trunk
 Left ventricle: opens to aorta – very muscular wall
 Interventricular septum: between the two ventricles
The heart – valves
 Atrioventricular valves (right and left AV valves)
o Each valve has a leaf-like cusps attached to coneshaped papillary muscles by tendons (chordae
tendineae)
 Right has three cusps (tricuspid)
 Left has two cusps (bicuspid, mistrial)
o When valve is open blood flows from A  V
o When closed blood exits ventricles
 Semilunar valves (right -pulmonary) (left- aortic)
o Each cusp is shaped like a cup
o When cusps are filled valve is closed to stop
backflow
o When cusps are empty valve is open blood exits
heart
The heart – great vessels
 Blood into the heart:
o Intro right atrium – superior and inferior vena cava
from systematic circuit
o Into left atrium – left and right pulmonary veins
from pulmonary circuit
 Blood out of the heart:
o Out of right ventricle – pulmonary trunk to
pulmonary circuit
o Out of left ventricle – aorta to systemic circuit
The heart – cycle and control
 Contraction of heart produces the pressure
o Blood moves through circulatory system from areas
of higher to lower pressure
 Cardiac cycle
o Repetitive contractions (systole) and relaxation
(diastole) of heart chambers – moves blood
o Blood flow is proportional to metabolic needs of
tissues
o Brain, kidneys, liver, exercising skeletal muscle –
very high
o Can change - cardiac output = heart rate x stroke
volume
 Nervous system:
o Maintains blood pressure and thus blood flow
 Hormonal control:
o Epinephrine (adrenaline) from adrenal gland –
increase HR and SV
The heart – conducting system
 Action potential – a rapid change in membrane
potential. Acts as an electrical signal / impulse
 The heart can generate its own action potentials
 Auto-rhythmicity – repetitive contractions

Sinoatrial node (SA) – pacemaker
 Atrioventricular node (AV)
 Action potentials spread through the conducting
system of the heart to all cardiac muscles cells – as a
result the cardiac muscle cells contract. Blood is
pumped
Compendium 6 – Lecture 2 of 2 How do things get around
the body? P2 Cardiovascular system – blood, blood vessels
and capillaries exchange
Why do we need a CVS?
 Transport
o Humans are multicellular
o Sales around the body only need a constant supply
of oxygen and nutrients and constant removal of
waste products
o we need a circulating fluid for transportation
o exchange materials between blood, cells and
extracellular fluid
o blood and blood vessels
o capillaries - exchange
 Pump:
18
generating blood pressure - move blood through
vessels
o routing blood - separates pulmonary and
systematic circulations
Blood -function
 transport – gases, nutrients, waste products, processed
molecules, hormones and enzymes
 regulation of pH and osmosis (normal 7.4)
 maintenance of body temperature
 shunting
 protection against foreign substances
 Clot formation
Blood – composition
 55% plasma (water, proteins and other solutes) and
45% formed elements (red blood cells, white blood
cells, platelets)
Blood -red blood cells
 Aka erythrocytes
 No nucleus and bi concave shape to increase SA and
thus oxygen carrying capacity
 Main component is a pigmented protein called
haemoglobin
 Oxygen from lungs to body cells: 1.5% dissolved in
plasma 98.5% attached to haemoglobin
Blood vessels – overview
 Arteries
o Elastic, muscular, arterioles
o Take blood away from the heart
o Contain blood under pressure
 Capillaries
o Site of exchange with tissues (interstitial fluid)
 Veins
o Venules, small, medium, large
o Take blood to the heart
o Thinner walls than arteries, contain less elastic
tissue less smooth muscle
o Valves to prevent backflow
Blood vessels – arteries and veins
 Tunica intima: simple squamous endothelium
 Tunica media: smooth muscle cells and elastin
arranged circularly
 Smooth muscle changes diameter of the lumen
 Tunica externa (adventitia): connective tissue
Blood vessels – capillaries
 Capillary beds – extensive networks for exchange
 Wall consists of endothelial cells (simple squamous
epithelium), basement membrane and a delicate layer
of C.T.
 Substances move through capillaries by diffusion
 Types
o Continuous
 No gaps between the endothelial cells
 Less permeable to larger molecules
 Found in muscle and nervous tissue
o Fenestrated
 Holes or fenestrae in the endothelial cells (70100nm diam.)
 Highly permeable
 Found in gut and kidney
o Sinusoidal
 Irregular incomplete wall of endothelial cells
o
 Larger in size – allows large molecules to pass
 Found in endocrine glands and liver
Capillary exchange
 Capillary exchange: the movement of substances into
and out of capillaries. How cells receive what they
need to survive and eliminate waste products
 Most important means of exchange: diffusion, Oxygen,
hormones, nutrients diffuse from a high concentration
in the capillary to low concentration in the interstitial
fluid
o Lipid soluble substances – diffuse trough plasma
membrane of epithelial cells
o Water soluble – diffuse through intercellular spaces
or through fenestrations of capillaries
o Large spaces between endothelial cells – proteins
and whole cells can pass
 Very small spaces between cells – very few molecules
can pass
 Capillary permeability, blood pressure, and osmotic
pressure affect movement of fluid from capillaries
 Cells are bathed in interstitial fluid (extracellular fluid)
 Transport (diffusion) in and out of cells – requires a
pressure gradient
 Interstitial fluid needs constant turnover
 Comes via capillaries and CVS
The lymphatic system
 Fluid moves out of capillaries into interstitial space and
most returns to capillaries
 The fluid which remains in tissues is picked up by the
lymphatic system then eventually returned to venous
circulation
Edema in lymphatic system
 Edema: swelling caused by excess fluid accumulated in
body tissues
 Causes:
o Problems with capillaries, hear failure kidney
disease etc.
 If capillaries become ‘leaky’ to blood proteins can leak
into interstitial fluid. This increases osmotic pressure
outside the capillary and draws more fluid from the
capillaries into the interstitial fluid
COMPENDIUM SEVEN: How do we get rid of
toxic waste?
Lecture
Compendium 7 – Lecture 1 of 2 How do we get rid of toxic
wastes? P1: the anatomy of the renal system
Gross anatomy of the renal system
 2 kidneys – formation of urine formation
 2 ureters – passage of urine
 Urinary bladder – storage of urine
 Urethra – passage of urine
Location of kidneys
 Posterior to the parietal peritoneum, on the posterior
abdominal wall, lateral to the spine
 Note the R kidney is slightly inferior to the L – due to
the position of the liver
 Partially protected by lumbar vertebrae and ribs
 Approx. 11cm long, 5 cm wide, 130g
Location and gross anatomy



19
Renal capsule – connective tissue surrounding each
kidney
Adipose tissue – surrounds the outside of the capsule
for protection
Renal fascia – thin layer of connective tissue surrounds
the adipose tissue, anchor kidneys to abdominal wall
Kidney internal anatomy
 Hilum: om the concave (medial side: renal artery and
nerves enter. Renal vein, ureter, lymphatics exit
 The hilum opens into the renal sinus which is filled with
fat and loose CT
 Kidneys are organised into two major regions
o Outer cortex
o Inner medulla
 Renal pyramids – bases project into cortex
 Renal columns are extensions of cortisol tissue into the
medulla
 Renal pyramids – bases project into cortex. Coneshaped. The base is the boundary between cortex and
medulla
 Apex of pyramid is renal papilla
 Papillae extend into minor calyces, which are funnelshaped chambers
 Minor calyces funnel into larger chamber called major
calyces
 Renal pelvis, a single large funnel-shaped chamber
 Renal pelvis is embedded in the renal sinus. At the
hilum, it narrows, forming the ureter
The nephron
 The functional unit of the kidney
 4 separate regions of the nephron: renal corpuscle,
proximal convoluted tubule, loop of Henle, distal
convoluted tubule
 Blood enters the nephron for filtration
 Filtrate/urine is produced
 Urine flow: nephron  papillary ducts  minor calyces
-> major calyces  renal pelvis  ureter
Types of nephrons
 Approximately 1.3 million nephrons in each kidney
 Approximately 50-55 mm in length
 Juxtamedullary nephrons:
o The renal corpuscle is deep in the cortex near the
medulla
o Long loop of Henle extending deep into the medulla
o 15% of nephrons
 Cortical nephrons
o Renal corpuscle located near the periphery/cortex
o Shorter loop of Henle
o 85% of nephrons
Renal Corpuscle
 The filtration portion of the nephron
 Consists of the glomerulus and the Bowman capsule
 Glomerulus:
o Network/ball of capillaries
 Bowman capsule:
o Enlarged end of the nephron, double walled
chamber. Filters blood/fluid, which then enters the
proximal convoluted tubule
 Blood enters glomerulus through afferent arteriole,
filtered blood exists through efferent arteriole
 Note size difference- pressure difference
Bowman Capsule
 Parietal layer
o Outer layer: simple squamous epithelium
o Becomes cuboidal in the PCT
 Visceral layer
o Inner layer. Constructed of specialized cells called
podocytes, which wraps around the glomerular
capillaries
The filtration membrane
 Fenestrae: the glomerular capillaries are highly
permeable. Fenestrae are little windows
 Basement membrane: sandwiched between the
endothelial cells of the glomerular capillaries and the
podocytes
 Filtration slits: gaps between the cell processes of the
podocytes
 Thus, the filtration membrane is specialized for
filtration
The renal tubules
 Proximal convoluted tubules: filtrate drains into here
from the Bowman capsule
 Loop of Henle has a descending and ascending limb
 Distal convoluted tubule: shorter than PCT
 Collecting duct: several DCTs connect to a single
collecting duct. Large diameter. Extends through
medulla towards renal papilla  ureter
Nephron histology
 Proximal convoluted tubule: simple cuboidal
epithelium with many microvilli. Mitochondria. Active
reabsorption of Na+, K+ & Cl Loop of Henle: thick pats – simple cuboidal epithelium.
Thin parts – simple squamous epithelium – for
osmosis/diffusion
 Distal convoluted tubule: simple cuboidal epithelium,
and very few microvilli. Numerous mitochondria.
Active reabsorption
 Collecting duct: simple cuboidal epithelium
Major Renal veins and arteries
 Abdominal aorta
 R. renal artery
 L. renal artery
 R. renal vein
 L. renal vein
 Inferior vena cava
Urine movement
 Pressure forces urine through nephron
20
Smooth muscles forces urine through ureters.
Peristalsis moves urine from the renal pelvis in the
kidneys  ureters  urinary bladder
 Ureters enter bladder obliquely through trigone.
Pressure in bladder compresses ureter and prevents
backflow
Ureters
 Passageway for urine
 From renal pelvis  urinary bladder
 Lined with transitional epithelium
Urinary bladder
 Hollow muscular container. Located in pelvic cavity
posterior to symphysis pubis
o Trigone: histologically unique region. Triangular
area on posterior wall between the entry of the two
ureters and the exit of the urethra
Urethra
 Transports urine from the urinary bladder to the
outside of the body
 Transitional epithelium at the top of the urethra; the
remainder is stratified columnar
 At the junction of the urinary bladder and the urethra
is the internal urinary sphincter
o Elastic CT and smooth muscle, prevents urine
leakage
 External urinary sphincter: skeletal muscle surrounds
urethra as it extends through pelvic floor.
o We can voluntary start/stop flow of urine
 Male urethra: extends from the inferior part of the
urinary bladder through to the tip of the penis
 Female urethra: shorter; opens into vestibule anterior
to vaginal opening
Compendium 7 – Lecture 2 of 2 How do we get rid of toxic
wastes? P2: the physiology of the renal system
Function of the renal system
 Excretion: rid the body of waste products. Urine
production occurs in the kidney via filtration of the
blood and reabsorption of nutrients. Metabolic wastes
and toxic molecules are excreted in urine
 Regulation of blood volume and blood pressure – we
control our extracellular fluid volume by producing
large amounts of dilute urine of small amounts of
concentrated urine
 Also – solute concentration in the blood, extracellular
pH, regulation of red blood cell synthesis, regulation of
vitamin D synthesis
The production of urine

Kidneys regulate body fluid composition. Sorts
chemicals in the blood for removal or for return into
the blood
 Nephrons: the structural component of the kidneys
that ‘sorts’ the blood
 Urine production: recall 3 stages – filtration, tubular
reabsorption, tubular secretion
Process 1: Filtration
 Movement of fluid, derived from blood flowing
through the glomerulus, across filtration membrane
 Filtrate: water, small molecules & ions that can pass
through membrane
o Doesn’t include red blood cells, proteins or large
molecules


Renal fraction: the proportion of total cardiac output
that passes through the kidneys
o Varies from 12-30% in a healthy resting adult
 Glomerular filtration rate (GFR): amount of filtrate
produced each minute – 125 ml/minute; 180 L/day
 Average urine production/day: 1-2L
 Most of filtrate (99%) must be reabsorbed
 Removes toxins quickly from blood
 The filtration membrane – remember the anatomy
o Fenestrae: the glomerular capillaries are highly
permeable. Fenestrae are little windows
o Basement membrane – sandwiched between the
endothelial cells of the glomerular capillaries and
the podocytes
o Filtration slits: gaps between the cell processes of
the podocytes
o Thus the filtration membrane is specialized for
filtration
 Filtration membrane – a filtration barrier
o Learn and remember the components of the
filtration membrane
o Filtrate consists of: water, glucose, fructose, amino
acids, urea, urate ions, creatinine, Na, Ca, Cl
 Very little protein normally found in filtrate
and urine
o Filtration is driven by pressure
 Blood pressure
o Filtration pressure: the force that causes filtration
 Pressure gradient responsible for forcing fluid
out of the glomerular capillary across the
membrane into the lumen of the Bowman
capsule
 The juxtaglomerular apparatus
o An important regulatory structure, located next to
the glomerulus
o Where the afferent arteriole enters the renal
corpuscle, a cuff of smooth mm cells surrounds it –
the juxtaglomerular cells
o A group of specialized cells at a section of the DCT –
called the macula densa
o These secrete renin, important in regulation of
filtrate formation and BP regulation
Process 2: Tubular reabsorption
 This is the return of water, small molecules and ions
back into the blood
 As the filtrate flows through the lumen of the renal
tubules
 First, substances are reabsorbed across the renal
tubule into the interstitial fluid, then from here into
the peritubular capillaries  back into the circulation
 Substances – water, amino acids, glucose, fructose, Na,
K, Ca, Cl, HCO3
 Proximal convoluted tubule – majority of reabsorption
here: filtrate remaining is about 35%
 Active and passive mechanisms of cell membrane
transport
 Note the apical surface of the PCT simple cuboidal
lining the nephron
o Borders with nephron lumen
 Note the basal surface borders with the interstitial fluid
21
Loop of Henle: some reabsorption of water and ions.
Remember thick and thin segments
o Thin segments – simple squamous epithelium,
highly permeable to water. And some solutes can
move by diffusion too
o Filtrate further reduced by another 15%
 Distal convoluted tubule and collecting duct: some
reabsorption
o Most of this is under control of Antidiuretic
hormone
 ADH makes the tubule wall more permeable
to water.
 Tubular reabsorption in the PCT
o Active transport of Na across the basal surfaces –
associated with the reabsorption of most solutes
o With Na being pumped out of the cell, the
concentration of Na is low inside the cell. Therefore
Na moves into the nephron cell through apical
surface. Other substances can move in by symport
 Glucose
Process 3: Tubular secretion
 The movement of non-filtered substances, toxic byproducts of metabolism, drugs or molecules not
normally produced by the body, into the nephron for
excretion. Occurs mainly in the distal convoluted
tubule
 As with reabsorption it can be active or passive
 Ammonia is a toxic by-product of protein metabolism.
Diffuses into lumen of nephron
 H, K and penicillin: actively secreted into nephron
Urine movement
 Pressure forces urine through the nephron
 Peristalsis moves the urine through ureters to urinary
bladder. Every few seconds to every few minutes
o Parasympathetic stimulation: increase frequency
o Sympathetic stimulation: decreases frequency
 Prevention of backflow of urine – trigone pressure
What is urine?
 1% of filtrate
 1-2L per day produced
 Proportion of water
 Depending on body’s needs
o Dilute or concentrated
 Urea, uric acid, ammonia, creatine, H, K
 Bile pigments
 Drugs and toxins e.g. penicillin
The micturition reflex
 While the flow of urine from ureter to bladder is
continuous, the flow from the bladder to urethra is not
 Bladder capacity 1L
 Micturition – elimination of urine from the bladder
 Full bladder – stretch receptors  CNS message
 Voluntary control (CNS) of the EUS. Relax  urination

COMPENDIUM EIGHT: How do we control
ourselves
Lecture Notes
Compendium 8 – Lecture 1 of 4 How do we control
ourselves? P1: Introduction to the nervous system
Functions of the nervous system
 Maintaining homeostasis

Receives sensory input
o Internal – e.g. stomach acids
o External – e.g. touch a hot stove
 Integrating information
 Motor output
 Establish and maintain mental activity
Structural divisions of the nervous system
 Central nervous system (CNS)
o Brain and spinal cord
 Peripheral nervous system (PNS)
o Spinal nerves and cranial nerves
Functional divisions of the nervous system
 Peripheral nervous system
o Autonomic nervous system (Automatic)
 Motor (efferent)
 Sensory (afferent)
o Somatic nervous system (Voluntary)
 Motor (efferent)
 Sensory (afferent)
o Enteric nervous system
 Motor (efferent)
 Sensory (afferent)
 Central nervous system
 Motor (efferent) can be divided into two parts
o Parasympathetic
o Sympathetic
Terminology
 Neuron: basic structural unit of the nervous system
 Axon: nerve fibre
 Nerve: bundle of axons (nerve fibres) and their sheaths
(outer covering)
 Sensory receptors: separate specialized cells which
detect temperature, pain, touch, pressure, light, sound,
odour and stimuli
 Action potential: electrical signal
 Effector organ / effector cell: organ, tissue or cell in
which the effect/action that takes place
 Ganglion: collection of cell bodies located outside the
CNS
 Plexus: extensive network of axons or cell bodies
 Synapse: junction of a neuron with another neuron
Autonomic subdivision
 Involuntary and under subconscious control
 Action potentials in the motor neurons travel from the
CNS to smooth or cardiac muscles or glands
 Two-neuron system
 Cell bodies of the neuron are located in the CNS and
autonomic ganglion
Somatic subdivision
 Voluntary and under conscious control
 Action potentials in the motor neurons travel from the
CNS to skeletal muscles
 Single neuron system
 Cell bodes are located in the CNS
Compendium 8 – Lecture 2 of 4 How do we control
ourselves? P2: Cells of the nervous system
Neuron
 Structural unit of the nervous system
 Dendrites
22
o Dendritic spines
 Cell body (soma)
 Axon
o Axon hillock
o Initial segment
o Trigger zone
o Axon collaterals
o Axon terminal or presynaptic terminals
o Terminal boutons or synaptic knobs
o
Types of neurons
 Functional classification
o Sensory neuron – information to the CNS
o Motor neuron – information away from the CNS
o Inter-neuron – information from one neuron to
another neuron
 Structural classification
o Multipolar – Many dendrites and a single axon (e.g.
motor neuron)
o Bipolar – axon, and dendrites (on either end) (rare –
found in eyes)
o Unipolar – axon only from the cell body (sensory
receptors)
Astrocytes cells
 From the CNS
 Abundant neuroglia cells in the nervous system
 Forming a supporting framework for blood vessels and
neurons
 Assist in the formation of tight junctions between
endothelial cells of the capillaries
 Respond to tissue damage in the CNS
Ependymal cells
 Line the central cavities of the brain and spinal cord
 Form lining of the cavities of the cerebrospinal fluid
Microglial cells
 Monitor the health of surrounding neurons
 Phagocytose microorganisms, infections, trauma or
inflammation
Oligodendrocytes
 Cover axons which form an insulating sheath around
them – myelin sheath
Cells of the PNS
 Schwann cells
o Also called neurolemmocytes
o Form a myelin sheath around axons  insulating
 Satellite cells
o Provide support and nutrition to cell bodies in
ganglia
o Protect cell bodies from harmful substances
Myelinated and unmyelinated axons
 Myelinated axons
o Nodes of Ranvier
 Unmyelinated axons
Grey and white matter
 Grey matter (cell body and dendrite) – CNS – brain:
outer cortex of brain and nuclei. SPINAL CORD – inner
part “grey” part
 Grey matter (cell body and dendrites) – PNS – ganglion
 White matter (axon) – CNS – brain: deeper nerve tracts
SPINAL CORD: outer part
 White matter (axon) – PNS – nerves
Compendium 8 – Lecture 3 of 4 How do we control
ourselves? P3: Electrical signals and action potentials
Electrical signals
 Action potential
 Membrane potential – the difference in charge across
the cell membrane
 Characteristics of the cell membrane which allows a
membrane potential to be generated
o Differences in ionic concentration (particularly for
Na+ and K+) across the cell membrane
o Permeability of the cell membrane to ions
Membrane ion channels
 Non-gated ion channels
o Also known as ‘leak’ ion channels
o Ion specific
o Cell membrane has more K+ leak ion channels to
Na+ leak ion channels
 Gated ion channels – require signals to open them
o Ligand-gated ion channel
o Voltage-gated ion channel
o Other-gated ion channel
Establishing resting membrane potential
 Resting membrane potential – the difference in charge
across the cell membrane in a resting cell
o Intracellular side is more negative
o RMP of neurons = -70mV where the negative sign
indicates the charge on the intracellular side of the
cell
 RMP caused by leak ion channels and the Na+/K+
pump
Changing the resting membrane potential
 Depolarisation – when the membrane potential
becomes more positive i.e. the inside of the cell
becomes more positive. E.g. -70mV  -30mV
 Hyperpolarisation – when the membrane potential
becomes more negative. i.e. the inside of the cell
becomes more negative E.g. -70mV  75 -75mV
 Repolarisation – membrane potential returns to
normal
Graded potential
 Graded potentials can lead to action potentials
 Graded potential – short lived, localised changes in
membrane potential
 Often occur in dendrites or the cell body of a neuron
 Ability to summate
 Decremental  not able to transfer information over
long distances
Action potential
 Afterpotential – short period of hyperpolarisation of an
action potential
 Action potential takes a few milliseconds
 Action potential s not decremental
Operation of gates: action potential
 Resting membrane potential
o All gated Na+ and K+ channels are closed
o K+ leaked channels are open which allows
movement of K+ to the outside of the cell. This
creates a negative intracellular charge =RMP
o Na+/K+ pump also creates the RMP
 Depolarisation
23
Na+ gated channels open and Na+ moves into the
cell and inside of the cell becomes more positive
o K+ gated channels are closed
o Membrane potential becomes more positive
 Repolarisation
o Na+ gated channels close
o K+ gated channels open and K+ moves out of the
cell and the intracellular side becomes more
negative
o Membrane potential becomes more negative
 End of repolarisation, and the afterpotential:
o Na+ gated channels close
o K+ gated channels close as well but they close
slowly so K+ continues to leave the cell and this
produces the afterpotential
o Membrane potential becomes very negative
 Resting membrane potential
o Na+ gated channels are closed
o K+ gated channels are closed
o Resting membrane potential is re-established by
Na+/K+ pump which redistributes ions as all Na+
and K+ gated channels are closed
Some relevant concepts to add
 All or none principle
 Refractory period
o Absolute refractory period
o Relative refractory period
Propagation of axon potentials
o


Takes place in unmyelinated axons only
Following depolarisation, each segment of the axon
membrane becomes repolarised
 The propagation of the action potential occurs in one
direction
 Saltatory conduction – myelinated axons
Compendium 8 – Lecture 4 of 4 How do we control of
ourselves? P4: Spinal reflex arcs
Introduction to spinal cord
 Meninges: connective tissue membrane surrounding
the brain and spinal cord
Reflexes
 Automatic response to a stimulus
 Are somatic or autonomic
 Homeostatic
 Components
o Sensory receptor
o Sensory neuron
o Interneuron
o Motor neuron
o Effector organ
 The simplest reflex arcs do not involve interneurons
o Monosynaptic vs. polysynaptic
COMPENDIUM NINE: HOW DOES IT ALL
WORK?
Lecture Notes
Compendium 9 - Lecture 1 of 4 How does it all work? P1:
The spinal cord and spinal nerves
Spinal cord
 Starts at the foramen magnum and extends inferiorly
to the first or second lumbar vertebrae
 Can be divided into cervical, thoracic, lumber, sacral
and coccygeal regions
 31 pairs of spinal nerves
 Dura mater – covering around spinal cord (protective)
 Cervical nerves (1-8 first nerves)
 Thoracic nerves (12 second set of nerves)
 Lumbar nerves (5)
 Sacral nerves (5)
 Coccygeal (1)
 Diameter of spinal cord changes from top to bottom
 Conus medullaris – finishes at the second lumbar
vertebrae
 Cauda equina
Meninges
 Meninges: the connective tissue coverage the spinal
cord and the brain
 Function
o Protects the CNS and blood vessels
o Contains the cerebrospinal fluid
o Forms partitions in the skull
 3 layers
o Dura mater – surrounds the brain and outer layer of
spinal cord
 Subdural space (space between dura matter
and arachnoid mater)
 Contains serous fluid
o Arachnoid mater – next layer of meninges
 Subarachnoid space
 Cerebrospinal fluid and blood vessels
o Pia mater
 Has many small blood vessels
 Grey matter contains cell bodies and dendrites
o Cortex of brain and muscles (CNS)
o Ganglion (PNS)
o Outer cortex (Brain)
o Inner (Spinal Cord)
 White matter contains myelinated and unmyelinated
axons
o Nerves tracts (CNS)
o Nerves (PNS)
o Deeper (Brain)
o Outer (Spinal Cord)
Organisation of neurons in the spinal cord and spinal
nerves
 Sensory neurons travel through the dorsal roots
 Motor (somatic and autonomic) neurons travel
through the ventral roots
24
Spinal nerves contain sensory neurons and motor
(somatic and autonomic) neurons
 Cell bodies of motor neurons are horns of grey matter
o Somatic motor neuron cell bodies in an anterior
(ventral) horn (motor horn)
o Autonomic motor neuron cell bodies in lateral horn
Nerve structure
 Endoneurium
o Surrounds each axon and its associated Schwann
cells
 Perineurium
o Surrounds a group of axons or a nerve fascicle
 Epineurium
o Surrounds a group of fascicles
Organisation of spinal nerves

Compendium 9 – Lecture 2 of 4 How does it all Work? P2:
The brain and cranial nerves
The brain
 Forebrain
o Cerebrum
o Diencephalon
 Midbrain
 Hindbrain
o Pons
o Medulla oblongata
o Cerebellum
 Midbrain, Hindbrain (Pons & Medulla) = brain stem
Medulla oblongata
 Autonomic reflex centre maintaining body homeostasis
 Cardiovascular centre
o Regulates heart rate, force of heart contraction and
blood vessel diameter
 Respiratory centre
o Regulates rate and depth of breathing
 Other reflexes
o Swallowing, vomiting, hiccupping, coughing and
sneezing
Pons
 Pons = bridge
 Contains conduction tracts:
o Longitudinal tracts from the spinal cord to higher
brain centres
o Transverse tracts form the cerebrum (motor cortex)
and cerebellum
 Sleep centre
o Rapid eye movement
 Respiratory centre
Midbrain

Receives visual, auditory and tactile sensory input
generating reflex movements of the head, eyes and
body
 Controlling movement of the eye
Cerebellum
 Cerebellum = little brain
 Controls locomotion, in association with the cerebrum
 Controls fine motor control
 Controls posture and balance
Diencephalon
 Thalamus
 Subthalamus
 Epithalamus
 Hypothalamus
Diencephalon: thalamus
 Sensory relay centre or “gateway”
o Anything you hear, see, feel by touch, but NOT
smell
 Regulates mood, memory and strong emotions
o E.g. fear and rage
Diencephalon: hypothalamus
 Maintains homeostasis via the endocrine system
 Regulates heart rate
 Regulates digestive activities
 Controls muscles in swallowing
 Controls body temperature
 Regulates sex drive and sexual pleasure
 Regulates mood, motivation and emotions
 Regulates the sleep-wake cycle
Cerebrum
 Longitudinal fissure – separates left and right
hemisphere
 Lateral fissure – separates the temporal lobe from the
rest of the cerebrum
 Central sulcus – separates frontal lobe from parietal
lobe
 Lobes:
o Frontal
o Parietal
o Occipital
o Temporal
o Insula
 Gyri – elevated tissue or folds
 Sulci – grooves
 Fissures – deep grooves
 Precentral gyrus – primary somatic motor cortex
 Postcentral gyrus – primary somatic sensory cortex
 Frontal lobe – voluntary motor function, motivation,
planning, aggression, sense of smell, regulation of
emotion behaviour and mood
 Parietal lobe – area which receives most the sensory
input, except from smell, hearing, taste and vision
 Occipital lobe – receives and processes visual input
 Temporal lobe – receives and processes smell and
hearing, and has a role in memory
 Insula – receives and processes taste information
 Grey matter in the cerebral cortex
o Cell bodies, dendrites, unmyelinated axons, axon
terminals and neuroglial cells
 White matter in the cerebral medulla
25
o Myelinated axons
 Corpus callosum – connects two cerebral hemispheres
together
Limbic system
 Role in memory
 Emotional brain
Meninges
 Dura matter
o Periosteal dura
o Dural venous sinus
 Venous blood
 Dural folds
o Meningeal dura
o Subdural space
 Serous fluid
 Arachnoid mater
o Subarachnoid space
 Cerebrospinal fluid and blood vessels
 Pia mater
o Has many small blood vessels
Ventricles
 4 ventricles that are continuous with each other
 Lined with ependymal cells

Lateral ventricle: first and second ventricle
 Third ventricle
 Cerebrospinal fluid produced in ventricles
Cerebrospinal fluid
 Most cerebrospinal fluid is produced by the choroid
plexus
 Fluid found around the brain and spinal cord
 Protects the brain and spinal cord from trauma and
provides buoyancy to the brain
 CSF composition: similar to blood plasma but less
proteins and different ionic concentration
Cranial nerves
 12 pairs
 Sensory, motor and/or parasympathetic functions
Compendium 9 – Lecture 3 of 4 How does it all work? P3:
The autonomic nervous system
Functional divisions of the nervous system
 Autonomic nervous system – motor neuron and
sensory
o Sympathetic and parasympathetic
 Somatic nervous system
o Motor & sensory
Anatomy of the autonomic nervous system
 Sympathetic division
o Thoracolumbar division T1-L2

Parasympathetic division
o Craniosacral division
 S2-S4
 Cranial nerve Nuclei
Functional generalisations of the sympathetic and
parasympathetic nervous systems
 Dual innervation of the autonomic nervous system
(ANS)
 Opposing effects
 Responses generated by both ANS divisions can
regulate:
o Heart rate
o Blood pressure
o Airway in lungs
o Digestive tract
o Glands (salivary, gastric, lacrimal)
o Pupil of the eye
 Sympathetic division:
o Fight or flight
o ‘E division’
 Exercise, emergency, excitement and
embarrassment
 Parasympathetic system
o Rest and digest
o D Division
 Digestion, defecation and diuresis
Regulation of the autonomic nervous system
 Autonomic regulation occurs mostly via autonomic
reflexes
o Reflexes are an automatic response to a stimulus
and are homeostatic
 Autonomic reflex activity is also influenced by the CNS,
in particular the hypothalamus
Compendium 9 – Lecture 4 of 4 – The endocrine system
Basics of chemical communication
 Autocrine
o Released by cells and have a local effect on same
cell type from which chemical signals are released
 Paracrine
o Released by cells and affect other cell types locally
without being transported in blood
 Neurotransmitter
o Produced by neurons and secreted into
extracellular spaces by presynaptic nerve terminals;
travels short distances; influences postsynaptic cells
 Endocrine
o Produced by cells of an endocrine glands, enter
circulatory system, and affect distant cells
Characteristics of the endocrine system
 Body control system where regulation requires
duration rather than speed
 Glands that secrete chemical messengers (hormones)
into circulatory system (blood)
 Hormone characteristics
o Produced in small quantities
o Transported some distance in circulatory system
o Acts on target tissues elsewhere in body
 Hormone secretion can be:
o Acute – sudden release due to stimulus e.g.
adrenaline
26
Chronic – small variations over long periods e.g.
thyroid hormones
o Episodic – e.g. estrogen and progesterone during
menstrual cycle
 Target cells respond to a hormone because they have
the correct receptor
Functions of the endocrine system
 Metabolism
 Control of food intake and digestion
 Tissue maturation
 Ion regulation
 Water balance
 Heart rate and blood pressure regulation
 Control of blood glucose and other nutrients
 Control of reproductive functions
 Uterine contractions and milk release
 Immune system regulation
Endocrine glands of the body
 Pineal gland
 Hypothalamus
 Pituitary gland
 Thyroid gland
 Parathyroid glands
 Thymus gland
 Adrenal gland
 Pancreas
 Ovary
 Testes
Nervous vs Endocrine systems
 Similarities
o Both systems associated with the brain
 Endocrine – hypothalamus
o Many use same chemical messenger as
neurotransmitter and hormone
 E.g. epinephrine
o Two systems are cooperative
 E.g. some parts of endocrine system
innervated directly by nervous system
(adrenal medulla)
 Differences
o Mode of transport
 Axon
 Blood
o Speed of response
 Nervous – instantaneous
 Endocrine – delayed
o Duration of response
 Nervous – seconds/ milliseconds
 Endocrine – minutes / days
Structure of the pituitary gland
 Posterior pituitary: extension of the nervous system via
the infundibulum
o Secretes neuropeptides
 Anterior pituitary: develops from embryonic oral
cavity; secretes traditional hormones
Pituitary gland and hypothalamus
 Where nervous and endocrine systems interact
 Hypothalamus regulates secretions of anterior pituitary
 Posterior pituitary is an extension of the hypothalamus
 The pituitary gland produces nine major hormones that
o
o Regulate body functions
o Regulate the secretions of other endocrine glands
 Hypothalamic control of posterior pituitary:
o Hormones produced in neurons in hypothalamus,
stored in posterior pituitary
 Axons from hypothalamohypophysial tract
o Action potentials in these neurons cause hormone
release
 Hypothalamic control of anterior pituitary
o Blood vessels make up hypothalamohypophysial
portal system, connect the areas
o Hypothalamic releasing and inhibiting hormones
stimulate or inhibit anterior pituitary hormone
release
Hypothalamus, anterior pituitary, target tissues
 Stimuli within nervous system regulate secretion of
releasing hormones from neurons in hypothalamus
 Releasing hormones pass to anterior pituitary
 Releasing hormones stimulates the release of
hormones from anterior pituitary
 Anterior pituitary hormones travel in blood stream to
target tissue, which may be another endocrine gland
Hypothalamic hormones
 Growth hormone-releasing hormone
o Causes increased secretion of GH
 Growth hormone-inhibiting hormone
o Causes decreased secretion of GH
 Thyrotropin-releasing hormone
o Causes TSH secretion
 Melanocyte releasing hormone
o Causes MSH secretion
 Corticotrophin-releasing hormone
o Causes ACTH secretion
 Gonadotropin-releasing hormone
o Causes secretion of gonadotropins LH and FSH
 Prolactin-releasing hormone
o Causes increased prolactin secretion
 Dopamine (prolactin-inhibiting hormone, PIH)
o Causes decreased prolactin secretion
Anterior pituitary hormones
 Growth hormone
o Acts on most cells of body overall metabolism and
growth
 Thyroid stimulating hormone
o Stimulates thyroid to secrete T3 and T4
 Adrenocorticotropic hormone
o Stimulates adrenal cortex to secrete cortisol and
aldosterone
 Melanocyte-stimulating hormone
o Causes melanocytes to produce more melanin
 Luteinizing hormone
 Follicle stimulating hormone
o Both hormones regulate production of gametes and
reproductive hormones
 Testes – to make testosterone and
spermatogenesis (sperm)
 Ovaries – to make estrogen and progesterone,
and oogenesis (oocytes)
 Prolactin
o Role in milk production (lactation)
Tropic vs Non tropic
27
Tropic hormones: stimulate the secretion of other
hormones from target tissues
 Non-tropic: initiate an effect
Hypothalamus, posterior pituitary, target tissues
 Stimuli within nervous system cause neurons in
hypothalamus to increase or decrease action potential
frequency
 AP’s conducted along neurons from hypothalamus to
posterior pituitary. Axon terminals of these neurons
store neuro-hormones
 AP’s cause release of neurohormones into circulatory
system
 Posterior pituitary hormones travel in blood stream to
target tissue
Posterior Pituitary hormones
 Antidiuretic hormone (ADH)
o Stimulates increased reabsorption of sodium and
water from nephrons, so less urine is produced. If
BP decreases, then ADH secretion is stimulated
o Also called vasopressin (vasoconstrictor, increase
BP)
 Oxytocin
o Uterine contractions during birth
o Ejection of milk from lactating breast (let down
reflex)
Control of hormone secretion – negative feed back
 Anterior pituitary secretes a tropic hormone which
travels in blood to target endocrine cell
 Hormone from target endocrine cell travels to it target
 Hormone from target endocrine cells has negative
feedback (opposite) effect on hypothalamus and
anterior pituitary to decrease secretion of tropic
hormone
Control of hormone secretion – positive feedback
 Anterior pituitary secretes a tropic hormone which
travels in blood to target endocrine cell
 Hormone from target endocrine cell travels to its
target
 Hormone from target endocrine cells has positive
feedback effect on hypothalamus and anterior pituitary
to increase secretion of tropic hormone
Growth hormone
 Stimulates uptake of amino acids, protein synthesis
 Stimulates breakdown of fats to be sued as an energy
source
 Promotes bone and cartilage growth
 Regulates blood levels of nutrients after a meal
 GH stimulates liver and skeletal muscles to make IGF-1
o Peak GH levels during deep sleep
Thyroid stimulating hormone T3 and T4
 Stress and hypothermia cause TRH to be released from
neurons within the hypothalamus. It passes through
the hypothalamohypophysial portal system to the
anterior pituitary
 TRH causes cells of the anterior pituitary to secrete
TSH, which passes through the general circulation to
the thyroid gland
 TSH causes increased synthesis and release of T3 and
T4 into the general circulation
 T3 and T4 act on target tissues to produce a response

28

T3 and T4 also have an inhibitory effect on the
secretion of TRH from the hypothalamus and TSH from
the anterior pituitary
Thyroid Gland
 One of largest endocrine glands
 Highly vascular
 Only gland that stores hormone
 Composed of follicles: follicular cells surrounding
thyroid hormones
 Iodine and tyrosine necessary for production of T3 and
T4
 Increase rate of glucose, fat, protein metabolism in
many tissues thus increasing body temperature
 Normal growth of many tissues
ACTH
 Near superior poles of kidneys
 (Adrenocorticotropic)
 Inner medulla; outer cortex
 CRH from hypothalamus causes release of ACTH from
anterior pituitary which causes cortisol secretion from
the adrenal cortex
 Causes aldosterone secretion from the adrenal cortex
 Causes androgen
ACTH – Cortisol
Adrenal Medulla
 Stress, physical activity, and low blood glucose levels
act as stimuli to the hypothalamus, resulting in
increased sympathetic nervous system activity.

An
increased frequency of action potentials conducted
through the sympathetic division of the autonomic
nervous system stimulates the adrenal medulla to
secrete epinephrine and norepinephrine into CVS.

Secretion of hormones prepares body for physical
activity. Short lived responses.
 Epinephrine and norepinephrine increase heart rate
and force of contraction; cause blood vessels to
constrict in skin, kidneys, gastrointestinal tract, and
other viscera.
Melanocyte stimulating hormone – MSH
 Acts on receptors in skin cells and stimulates melanin
in the skin
 MSH also has a role regulating appetite and sexual
behaviour
 Poorly understood
LH and FSH
 GnRH from hypothalamus stimulates LH and FSH
secretion
 Gonadotropins: glycoprotein hormones that promote
growth and function of the gonads
 LH and FSH
o Both hormones regulate production of gametes and
reproductive hormones
o Frome testes – testosterone: spermatogenesis,
secondary sex characteristics
o From ovaries – estrogen and progesterone: sex
organ development and characteristics, menstrual
cycle, pregnancy
Prolactin
 Non tropic hormone
 Breast milk production
 Supply and demand
Oxytocin
 Posterior pituitary
 Non-tropic hormone
 Positive feedback
 Breast milk release (let down)
 Supply and demand
ADH
 Reduced urine formation.
 Keeps water in the body
 Increases blood volume and thus blood pressure.

Hot day / dehydrated = lots of ADH.
 Diuretic – tea, coffee, alcohol
Pancreas – regulation of insulin secretion
 Located along near intestine and stomach;
retroperitoneal
 Exocrine gland: Produces pancreatic digestive juices
 Endocrine gland: Consists of pancreatic islets.
 Alpha cells - secrete glucagon
 Beta cells - secrete insulin
Endocrine pancreas – regulation
COMPENDIUM TEN: HOW DO WE PROTECT
OURSELVES?
LECTURE NOTES
Compendium 10 – How do we protect ourselves? –
Lecture 1 of 2 – P1: Immunity
Pathogens & antigens
 Pathogen – foreign agents
o Protozoa
o Viruses
o Worms
o Toxins
o Fungi
o Prions
 Bacteria – infection, food poisoning
o Pathogens introduce foreign (non-self) proteins in
the body called antigens
o Antigenic receptors on T cells and B cells recognize
these foreign proteins as not being “self” and aims
to remove them from the body
Immunity
 Ability to resist damage from foreign substances and
internal threats
 Can be distinguished between “self” and “non-self”
o External – micro-organisms e.g. bacteria, virus,
fungi, toxins
o Internal – cancer cells
 Categories
o Innate or nonspecific immunity
o Adaptive or specific immunity
 Innate and adaptive immunity are fully integrated in
the body
Immune system vs. lymphatic system
 Lymphatic system
o Transport system for cells of the immune system
and antigens (foreign substances/cells) to move
around the body
29
Tissues where cells of the immune system “hang
out”
 Immune system
o Collection of proteins, cells, tissues and organs
widely distributed throughout the body
Immune system
 Immunity: ability to resist damage from foreign
substances e.g. microbes chemicals and internal
threats (e.g. cancer)
 Innate (non-specific)
o Physical barriers - skin & mucous membranes
o Inflammation
o Chemical mediators
o White blood cells (leukocytes) e.g. macrophages
 Adaptive (specific)
o Cell mediated immunity – T cells
o Antibody mediated immunity – B cells
Innate immune system
 Non-specific defence, present at birth
 Each time body is exposed to a substance, response is
the same (no memory)
 Provides immediate protection from pathogens &
antigen
 First line of defence are external features
o Physical barriers
 Second line of defence
o Chemical mediators
o White blood cells
o Inflammation
o fever
Innate immunity:
1. physical
 Physical barriers – prevent entry or remove microbes
o Skin
o Mucous
o Saliva
o Tears
o Acid in stomach, urinary tract, vagina
o Urine flushes urinary passageways
o Cilia in respiratory tract, coughing and sneezing
2. Chemical mediators
 Chemical mediators – promote phagocytosis and
inflammation
o Promote inflammation
 E.g. histamine
 Cause vasodilation, increased vascular
permeability, attract white blood cells,
stimulate phagocytosis
o Cytokines
 Secreted by one cell, and stimulates a
neighbouring cell to respond
 Regulate intensity and length of immune
response
o Complement – stimulate lysis of invading pathogen
cells
o Interferons – anti-viral activity
3. white blood cells
 White blood cells produced in bone marrow &
lymphatic tissue
 Released into blood and transported around the body
o

When a tissue is damaged it releases chemicals that
attract white blood cells
 White blood cells ingest foreign particles –
phagocytosis
 Produce chemicals to attract other immune cells to
local area
 Neutrophils and macrophages are most important
phagocytic cells
o Neutrophils
 First cell to arrive at a site of insult
o Macrophages
 Most effective phagocyte, important in
later stages of inflammation and repair
 Help activate cells of the specific immune
system
 Basophils, eosinophils, Natural killer cells
4. Inflammation
 Local tissue response to damage
o Pathogens
o Cuts and abrasions
 Aims to
o Rid of body debris/invader
o Prevent further pathogen entry
 Four features
o Redness – increased blood flow to region
o Heat – increased blood flow to region
o Swelling – capillaries become leaky (increased
permeability) fluid leaves capillaries – surrounding
tissue
o Pain – increased fluid stimulates pain receptors,
chemical released by cells can also stimulate pain
receptors
Inflammatory response
 Heat, redness, swelling & pain
5. Fever
30
Generalized response of the body to tissue damage &
infection
 Common in inflammation and infection
 Can cause macrophages to release chemicals
 Body temperature abnormally high
 High temperatures
o Increase some antimicrobial substances
o Decrease microbial growth
o Increase body reactions that help tissue repair
Adaptive immunity
 Specificity – ability to recognise a particular substance
 Memory – ability to remember previous encounters
with a particular substance and respond rapidly

Acquired during lifetime, depending on exposure
 Fights invaders once innate system is over-run
 Mediated by lymphocytes (special type of white blood
cells ) B & T cells
 Activation of lymphocytes
o Lymphocytes must recognise antigen
o After recognition, lymphocytes must increase in
number to destroy antigen
 Helper T cells
 Effector (cytotoxic/killer) T cells
 B Cells
Cell-mediated immunity
 T lymphocytes
o Helper T cells
o Cytotoxic T cells
 Activated by special antigen
 Specific “clones” bind to antigen
 Co-stimulation required (Helper T cells)
 Activated cytotoxic T cells divide
 Eliminate antigen (pathogen) – makes holes in cell wall
and causes cells to explode
 Form memory cells – if the same antigen re-appears,
the response will be faster (memory)
 Most effective against intracellular pathogens
Antibody-mediated immunity
 B cells
 Phagocytosis of an extracellular pathogen that matches
the specific B cell receptor on that B cell
 Required co-stimulation by a helper T cell that also
recognises the same pathogen (antigen)
 B cells divide to form
o Plasma cells – make antibodies
o Memory B cells – if the same pathogen (antigen) is
encountered again, the response is much faster

31
Antibody production
 Primary response
o when a B cell is first activated by an antigen.
o B cell proliferates to produce plasma cells
(antibody production) and memory cells.
 Secondary response
o occurs during later exposure to same antigen.
o Memory cells divide rapidly to form plasma cells
and additional memory cells. Faster and greater
response.
Ways to acquire adaptive immunity
Immune interactions
Immune system dysfunction – HIV
 HIV = human immunodeficiency virus

Virus binds to CD4 protein and infects Helper T cells
 Cells infected with HIV are ultimately destroyed by the
virus or by immune response
 Gradual destruction of Helper T cells impairs cell
mediated and antibody mediated immunity
 Normal amounts of Helper T’s = 1200 cells/mm3
 When Helper T’s get below 200 cells/mm3
 Acquired immune deficiency syndrome (AIDS)

Antibody levels decline and cell mediated immunity
reduced
 Believed to have spread from The Congo to Haiti to US
in late 1960’s/70s
 First described by the CDC in the US in 1981
o Long incubation period, and initially low incidence
rate
 Initially reported mainly the gay community, IV drug
users, people who received blood transfusions
HIV-AIDS
 Body is vulnerable to microbial invaders
 Ordinarily harmless microorganisms can cause lethal
infections
o Pneumocystis pneumonia
o TB, syphilis
o candidiasis
 Increased risk of cancer – Kaposi’s sarcoma

Infection due to intimate contact with body fluids of
infected people
 Treatment
o When first described no treatment available
 HIV pretty much considered a “death
sentence” (see Grim Reaper ad, Australia,
1987)
1. control HIV replication
o Highly active anti-retroviral therapy (HAART)
o Can live for many years
o Chronic disease rather than death sentence
32
Lymphatic organs contain lymphatic tissue
o Lymphocytes, macrophages, dendritic cells
 Lymphocytes: B & T cells – white blood cells derived
from bone marrow
 Fine network of reticular fibres. Produced by reticular
cells. Act as filter to trap microorganisms and other
particles
 May be encapsulated (in a CT capsule)
o Encapsulated – lymph nodes, spleen, thymus
o Nonencapsulated – mucosa-associated lymphoid
tissue (MALT). Found beneath epithelium as first
line of attack against invaders
Diffuse lymphatic tissue & lymphatic nodules
 Diffuse lymphatic tissue:
o Dispersed lymphocytes, macrophages; blends with
other tissues
 Lymphatic nodules:
o Denser aggregations. Numerous in loose connective
tissue of digestive, respiratory, urinary,
reproductive systems
Lymph nodes
 Only structures to filter lymph
 Substances removed by phagocytosis or stimulate
lymphocytes to proliferate
o Cancer cells often migrate to lymph nodes, are
trapped there, and proliferate. Can move from
lymphatic system to circulatory system spreading
cancer throughout the body
 Afferent and efferent vessels
 Organized into cortex and medulla with dense
connective tissue capsule surrounding
2. manage secondary infections/malignancies
Compendium 10 – How do we protect ourselves? –
Lecture 2 of 2 – P2: Lymphatics
Functions of the lymphatic system
 Fluid balance
o Excess interstitial fluid enters lymphatic capillaries
and become lymph (30L from capillaries into
interstitial fluid, 27L return leaving 3L called lymph)
 Fat absorption
o Absorption of fat and other substances from
digestive tract via lacteals
 Defence
o Lymphatic system – fights infection.
Microorganisms and other foreign substances are
filtered from lymph and by lymph nodes and from
blood by spleen
Anatomy of the lymphatic system
 Lymph
 Lymphatic vessels
 Lymphatic tissue
 Lymphatic nodules
 Lymph nodes
 Tonsils
 Spleen
 Thymus
Lymph
 Water plus solutes from two sources
o Plasma: ions, nutrients, gases, some proteins
o Cells: hormones, enzymes, waste products
 Returns to circulatory system via veins, essential for
fluid balance
Lymphatic vessels
 Carry lymph away from tissues
 Lymphatic capillaries
o More permeable than blood capillaries
o Epithelium functions as series of one-way valves
o Found in all parts of the body except nervous
system, bone and avascular tissues
 Lymphatic capillaries: join to form lymphatic vessels
 Lymphatic vessels: have valves that ensure one-way
flow
 Lymph nodes: distributed along vessels and filter
lymph
 Lymphatic trunks: jugular, subclavian, broncho
mediastinal, intestinal, lumbar
 Lymphatic ducts: drain tissues of body and move lymph
onto major veins
o Right lymphatic duct: drains right side of head,
right-upper limb, right thorax
o Thoracic duct: drains remainder of the body

Lymphatic tissue and organs
Tonsils

Large groups of lymphoid tissue in nasopharynx and
oral cavity
 Provide protection against bacteria and other harmful
material
o Palatine (tonsils)
o Pharyngeal (adenoids)
o Lingual
Spleen
 Red pulp associated with veins (75%) – fibrous network
of macrophages and RBCs
 White pulp associated with arteries (25%) – lymphatic
tissue
 Functions
o Monitors blood, detects and responds to foreign
antigens
o Destroys defective red blood cells
o Regulates blood volume
o Limited reserve of RBC
 Can be ruptured in traumatic abdominal injuries
 Splenectomy
Thymus
 Located in superior mediastinum
 Cortex (numerous lymphocytes) and medulla (fewer)
 Sites of maturation of T cells: many T cells produced
here, but most degenerate
 Those that remain can react to foreign substances
 Endocrine functions
Disorders
 Tonsilitis – inflammation of the tonsils – bacterial
infection
 Lymphoma – cancer (benign or malignant) of the
lymphoid tissue or cells, often begins in the lymph
nodes, immune system suppressed
 Hodgkin’s disease – malignancy in lymphoid tissue
(malignant B cells). Chemotherapy/radiation
 Non-Hodgkin’s lymphoma – any cancer of lymphoid
tissue – except Hodgkin’s. Can affect cells, nodes or
organs. Young vs Old
 Bubonic plague (the black death) – severe bacterial
infection (fleas/rats), enlarged lymph nodes,
septicaemia
COMPENDIUM ELEVEN: HOW DO CELLS
SPECIALISE AND DIE?
Compendium 11 – How do cells specialise and die? Lecture
1 of 4 – P1: Introduction to DNA
Introduction to DNA
 DNA; deoxyribonucleic acid
 Genetic information contained in nucleus
 Contains genetic information for protein formation
 Approximately 23 000 genes in human genome
 Genes code for proteins
 Only 1.5% of DNA is due to genes
 98.5% of DNA is non-coding – e.g. regulatory
sequences, introns and noncoding DNA – e.g. repeat
elements
Structure of DNA
 Double-stranded (double helix twisted ladder)
 Sugar phosphate backbone
 Complementary nitrogenous bases
o Adenine – thymine
33
o Guanine – cytosine
Organisation of DNA
 Double strand of DNA – twisted ladder
 DNA wrapped around proteins called histones
 Histones & DNA bundled together – chromatin
 Chromatin twists around to make chromosomes
How much DNA is in a cell?
 Each somatic human cell has two copies of each
chromosome – one you inherit from each parent
 The maternal and paternal chromosomes of a pair are
called homologous chromosomes
 Humans have 22 pairs of autosomal chromosomes and
1 pair of sex chromosomes
o Women have 2 X chromosomes and men have an X
and Y
 Somatic cells with 46 chromosomes (23 pairs) are said
to be diploid (have the full amount of DNA)
 Gametes (sperm and egg) only have 1 chromosome of
each homologous pair (have 23 chromosomes) and are
called haploid
 When cells are dividing, the chromosomes become
easier to see and we can arrange them next to their
pair – this kind of map is a karyotype
Definitions
 Genetics – study of heredity
 Gene – piece of DNA that codes for a protein
 Allele – alternative form of a gene
 Genotype – the actual gene (allele)
 Phenotype – person’s appearance
 Dominant and recessive alleles

Sex-linked traits: traits affected by genes on sex
chromosomes
Compendium 11 – How do cells specialise and die? Lecture
2 of 4 – P2: Protein synthesis
The “proteome”
 Cells are protein factories that constantly synthesise
many different proteins
 These proteins are used for cell functions or can be
exported
 The cell’s DNA contains all the instructions the cell
needs for making proteins
 Not all cells make proteins – some proteins are needed
only by specific cells
o The “proteome” of a cell is all the proteins that a
cell makes, and “proteomics” is the study of the
proteins in a cell
o The proteome of one cell can be compared to
another to see how they are different
 A muscle cell vs a skin cell
Protein synthesis
 Transcription
o DNA > RNA
 Translation
o RNA > protein
 Flow of information from DNA to RNA to protein: The
Central Dogma
Transcription
 DNA has two strands, but only one strand of the DNA is
used as a template to make RNA

Genetic information (a gene) is copied from strand of
DNA to make a strand of ribonucleic acid (RNA) called
mRNA (messenger RNA)
 RNA is like DNA except –
o Sugar ribose instead of deoxyribose
o It is single-stranded
o Contains uracil instead of thymine
 RNA acts as an intermediary between DNA and protein
 Initiated by transcription factors that recruit RNA
polymerase enzyme
 The mRNA produced is called an RNA transcript
 There are special sequences/signals in DNA that
indicate when a gene starts and stops
 Within a gene there are exons (coding) and introns
(non-coding)
 The initial mRNA transcript (pre-mRNA) contains both
the exons and introns
 The RNA introns are the cut out and the exons are all
joined together. This transcript is called processed RNA
 Three kinds of RNA are transcribed from DNA
o Messenger RNA (mRNA) – is translated in the
cytoplasm to make proteins
o Ribosomal RNA (rRNA): together with ribosomal
proteins rRNA makes up the ribosomes
o Transfer RNA (tRNA): each tRNA can bind
specifically to one of the 20 different amino acids
used to build proteins, important in translating
mRNA into amino acid peptide
 The strands of DNA are separated
 RNA polymerase binds at a promoter region

RNA polymerase catalyses the formation of a mRNA
chain using the DNA as a template and following the
rules of complimentary base pairing
o A with U
o C with G
 Transcription ends at a terminator sequence
Translation
 Turns mRNA into a protein
 Occurs in the cytoplasm – by ribosomes
o On rough ER
o Free within cytoplasm
 mRNA carries genetic information from the nucleus to
the ribosomes
 The sequence is “read” by translational machinery in
the ribosome, in lots of three nucleotides (nucleotide
triplets = codon)
 Translation starts at the start codon (AUG) of each
gene in the mRNA
 Each codon codes for a specific amino acid
 As each codon is read, a tRNA with a complimentary
sequence (anticodon) binds to each triplet
 The tRNA also carries the amino acid specified by the
codon
 Amino acids are joined together by peptide bonds, in
the sequence specified by the mRNA, to make a
peptide/protein
Codons & amino acids
 There are 64 possible codons in mRNA and only 20
naturally occurring amino acids
 Some amino acids are specified by only one codon
34
Others are specified by up to six different codons
Thus the DNA code is “degenerate”
Three codons do not code for an amino acid but signal
termination of the peptide chain
Post-translational modification
 The chemical modification of a protein following
translation
 It is one of the last steps in protein synthesis
 After translation, proteins can be modified by attaching
other functional groups which can change or extend its
functions
 Amino acids may be cleaved off the end of protein or
the polypeptide can be cut in half
 Other modifications, such as phosphorylation are a
common way of controlling the behaviour of a protein,
for instance activating or inactivating an enzyme
Compendium 11 – How do cells specialise and die? Lecture
3 of 4: P3: Protein structure
Protein structure
 A protein molecule is a long chain of amino acids, each
linked to its neighbour by a peptide bond
 There are many thousands of proteins, each has a
unique sequence of amino acids
 Each amino acid has specific properties due to its side
chains
 Some of the side chains are non-polar and hydrophobic
(water fearing), others are hydrophilic or positively or
negatively charged
 In a long chain of amino acids, interactions between
these side groups, as well as the peptide bonds, affect
the way a protein can fold and what shape it is
 Peptide – 2 or more amino acids
 Polypeptide – 10 or more
 Protein – 50 or more
 Primary
o Sequence of amino acids linked by peptide bonds
 Secondary
o Proteins fold to form secondary structures because
the amino acids have different side chains
o Two regular folding patterns are seen: alpha helices
and beta pleated sheets
 Tertiary
o The 3D shape is determined by the folding of the
secondary structure. The a-helices and b-sheets
fold to form unique structures which are held
together my bonds between amino acids that may
be far apart in the actual polypeptide chain
 Quaternary
o Combined three-dimensional structure of two or
more polypeptide chains
o E.g. haemoglobin
Fibrous and globular proteins
 The 3D structure of a protein is related to its function
 Proteins can be classified according to overall shape
and appearances as whether fibrous or globular
 Globular proteins
o Polypeptide chain folds up into a compact shape,
like a ball with a rough surface
o Usually water soluble
o Mobile
o Chemically active



o Plays crucial roles in nearly all biological processes
 Fibrous proteins
o Simple, elongated 3D structures
o Are insoluble in water and stable
o Provide mechanical support and tensile strength
o Are abundant outside the cell where they make up
a lot of the matrix in between cells
Compendium 11 – how do cells specialise and die? Lecture
4 of 4: P4: Mitosis and Meiosis
Cell life cycle
 Cells spend the majority of their life in interphase
 Interphase: phase between cell division. Ongoing
normal cell activities
 Mitosis: series of events that leads to the production of
2 somatic cells by division or one mother cell into two
daughter cells. Cells are genetically identical
o Prophase
o Metaphase
o Anaphase
o Telophase
 Cytokinesis: division of cell cytoplasm
Chromosomes & chromatin
 Chromatin: DNA complexed with proteins (histones)
 During cell division, chromatin condenses into pairs of
chromatids called chromosomes. Each pair of
chromatids is joined by a centromere
Chromosomes
 Humans: 23 pairs of chromosomes. 46 diploid number,
22 autonomic pairs
 1 sex determining pair
 Homologous: pairs of chromosomes -where one is
from father and mother is from mother
 Locus: the location of a gene on a chromosome
 Allele: different forms of the same gene
DNA replication
 Interphase – DNA replication occurs. Each
chromosome becomes doubled, consisting of 2
identical strands of DNA
Structure of a mitotic chromosome
 The DNA of a chromosome is dispersed as chromatin
 The DNA molecule unwinds, and each strand of the
molecule is replicated
 During mitosis, the chromatin from each replicated
DNA strand condenses to form a chromatid. The
chromatids are joined at the centromere to form a
single chromosome
 The chromatids separate to form two new, identical
chromosomes. The chromosomes will unwind to form
chromatin in the nuclei of the two daughter cells
Mitosis
 Produces 2 identical daughter cells
 Prophase – chromatin condenses to form
chromosomes, centrioles migrate to end of each cell,
spindle fibres attach to centromeres, nuclear envelope
disintegrates
 Metaphase – chromosomes are aligned at the nuclear
equator
 Anaphase – spindle fibres separate the chromatids, 2
identical sets of chromosomes are moved to separate
ends of the cell, cytokinesis begins
35
Telophase – nuclear envelope reforms around each set
of chromosomes, chromosomes decondense into
chromatin, cytokinesis continues
Centrioles & spindle fibres
 2 centrioles, located in centrosome
 Centre of microtubule (spindle fibre) formation
 Before cell division, centrioles divide, move to ends of
cell and organise spindle fibres
 Mitosis I.P.M.A.T
Meiosis
 Germ cells divide and produce gametes
 Specialized for sexual reproduction
 DNA replication followed by two cell divisions
 Produces 4 genetically different daughter cells
o Gametes (haploid)
o Only 1 homolog from each homologous pair
 Resulting gametes unite to form a zygote – a new
“genetically unique” human being
Spermatogenesis
 Where is meiosis happening?
 In the gonads.
 The testes make gametes (sperm) via meiosis. 4
functional sperm cells per division.
 Non identical.
 23 chromosomes.
 Lifelong process in testes.
Oogenesis
 The ovaries make gametes (oocytes) via meiosis.
 At birth, the ovaries contain all the oocytes they will
ever have – stalled in prophase 1.
 1 functional oocyte per division.
 3 polar bodies.
 Non identical.
 23 chromosomes
