MC1 - Anatomy and physiology
The Human Body
I.
Introduction to Anatomy and Physiology
Terminologies
Anatomy
-Study of structure and shape of the body and its parts
-Observation is used to see sizes and relationships
: Anatomy= Greek “Temneien” or tomy meaning “to cut”
= “Ana” meaning “a part”
- The study of the structure and see the shape, sizes of the body and its parts and their
relationships to one another.
Physiology
-
Study of how a body structure and its parts work or function.
Structure = determines what functions can occur; therefore, if the structure
changes, the function must also change.
: Physiology= Physio = nature : Ology = the study of
For example:, the air sacs of the lungs have very thin walls, a feature that enables
them to exchange gases and provide oxygen to the body.
Structure = Determines what functions can occur; therefore if the structure changes, the function
must also change.
Types of study
1.) Regional Anatomy approach=each region of the body is studied separately, and all aspects
of that region are studied at the same time. One organ cannot stand alone, all organs are
interconnected
2.) Systemic Anatomy Approach= each system of the body is studied and followed throughout
the entire body.
= 11 Major human body systems (Integumentary System; Skeletal System;
Muscular System; Endocrine System; Cardiovascular System; Lymphatic System;
Respiratory System; Digestive System; Urinary System; Reproductive System)
3.) Surface anatomy approach= Superficial (Can be seen:external) study of the part. The
surface level of the body.
Types of Anatomy
1. Gross Anatomy = Large structures; Easily observable
2. Microscopic anatomy = Very small structures; Can only be viewed with a microscope.
Histology.
Types of Physiology
1. Systemic Physiology = All aspects of the functioning of specific organ systems.
2. Cellular Physiology = The biological study of the activities and the functions that take place
in a cell to keep.
Levels of Structural Organization: (1) Chemical Level (atoms combine to form molecules) => (2)
Molecules => (3) Cell (smallest unit of life) made up of molecules = (4) Tissue level consist of
similar types of cells => (5) Organ level- Organ are made up of different types of tissue. => (6)
Organ system => (7) Organism - Human organisms are made up of many organ systems.
Organ System Overview
Integumentary
- Forms the external body covering:
Skin.waterproofs the body and cushions
-Protects deeper tissue from injury
-Excretes toxic products during respiration Excretes salts and urea in perspiration
-Help regulate body temperature - Dilated
vessels allow for heat loss while constricted
vessels retain heat
-Synthesizes vitamin D
-Location of cutaneous nerve receptors
Skeletal system
-Protects and supports body organs
-Provides muscle attachment for movement
-Site blood cell =Hematopoiesis
-Stores house of minerals
Muscular System
-One Function is to contract
-Voluntary and involuntary
- Allows locomotion and facial expression
-Maintains posture
-Produces heat
Nervous System
-Fast-acting control system
- Responds to internal and external changes
Endocrine System
- controls the body activities
-Secretes regulatory
-Hormones + responsible for growth;
reproduction; metabolism
Cardiovascular system
- The blood used as transporting fluid:
Oxygen; Hormones; Nutrients.
- The white blood cells help to protect
the body from foreign invaders.
- The heart pumps blood
Lymphatic System
- Returns Fluids to blood vessels. Fluids
shift to intercellular and extracellular.
Circulation includes the excretion of
other fluids.
- Disposes of debris in the lymphatic
stream.
- House the white blood cells involved
in immunity.
Respiratory System
-
Keeps blood supplied with oxygen
Removes carbon dioxide
Exchange of gas are made to and from
the blood
Digestive System
- Breaks down food into absorbable
unit
- Allows for nutrient absorption into
blood to be used by the cells
- Eliminates indigestible material
-
-
Other structures:
- mAle serve as aid in the
delivery of sperm to the fem
rep organ and for fem site of
fertilization
Mammary Gland (produces milk) for
the newborn.
Urinary/Excretory System
- Eliminates nitrogenous wastes
- Maintained acid-base balance
- Regulates water and electrolytes
Reproductive system
- Overall production of offspring
- Testes produce sperm (male)
- Ovaries produces egg cells (female)
Necessary Life Function = in order for the body to maintain itself.
Maintain Boundaries
- So that inside remains distinct from the outside and inside.
- The integumentary system (skin) protects the internal organs from drying.
- The digestive system takes in nutrients.
- The respiratory system take in oxygen
- Urinary system eliminates metabolic wastes from the body
Movement
- Accomplish by muscular system together with the skeletal system
- And other substances in the body are moving chemically, such as the blood flow, digestion
of food and urinating.
Responsiveness/ Irritability
- Ability to sense changes (stimuli and react in the environment
- Nerve cells are highly irritable and communicate with each other by conducting electrical
impulses. Transmission of stimuli > Actives the gland > Sends out necessary hormones.
- Major responsibility
Digestion
- Breakdown and delivery of the system
- The process of breaking down ingested food into simple molecules that can then be
absorbed into the blood.
- The nutrient-rich blood is then distributed to all body cells by the cardiovascular system,
where body cells use these simple molecules for energy and raw materials.
Metabolism
- Chemical reactions within the body cells.
- Production of energy: breaking down complex substances into simpler building
blocks (as in digestion), making larger structures from smaller ones, and using
nutrients and oxygen to produce molecules of adenosine triphosphate (ATP),
energy-rich molecules that power cellular activities.
- Making body structures:
Excretion
- Elimination of waste products
Reproduction
- Production of future generation in cellular or organismal level.
Growth
- Increasing of cell size and number
Ketosis is a temporary form of a negative feedback of homeostasis
The Language of Anatomy
This is a system composed of special terminology and symbols unique to the human body
for us to better understand its concepts and principles and to avoid confusion.
Anatomical Positions
- Standard position - reference point
- Accurately describe body parts and position; to avoid confusion.
- Initial reference point and used directional terms regardless of the position
4 criterions to determine an anatomical position:
1. The body should be standing erect.
2. Arms at the side
3. Palms facing forward and the thumbs pointing away from the body
4. Feet slightly apart.
1.) Directional terms = Explains the location of the body structure in relation to another
Directional Terms:
1. Superior (Cranial or Cephalic )
= Toward the head or upper part of the structure ; ABOVE
2. Inferior (Caudal)
=Away from the head or toward the lower part of a structure or the body; BELOW
Ex: The nose is superior to the mouth
The mouth is inferior to the nose
---------------------3. Anterior (Ventral)
= Toward the front of the body; INFRONT
4. Posterior (Dorsal)
=Toward the at the backside of the body; BEHIND
Ex. The breastbone is anterior to the spine
The spine is posterior to the breastbone
The kidneys are posterior to the abdominal wall.
The abdominal wall is anterior to the kidneys
--------------------5. Medial
=Toward or at the midline of the body ; ON THE INNER SIDE OF/ INWARDS
6. Lateral
=Away from the midline of the body; ON THE OUTER SIDE OF/ OUTWARDS
7. Intermediate
=Between a more medial and more lateral structure of the body
*Note: The midline of the body is vertical.
Ex. The heart is located in the middle of the left and right lung:
- The heart is medial to the lungs
- The lungs are lateral to the heart
The eyes are located in the middle of the nose and the ear:
- The eyes are intermediate to the nose and the ear
--------------------8. Proximal
=Close to the origin of the body point of the attachment to a limb to the body trunk
9. Distal
=Farther from the origin of a body part or the point of attachment of a limb to the body
trunk
Ex. The knee is proximal to the ankle (since the knee is nearer to the hip or point of
attachment compared to the knee)
The ankle is distal to the knee (since the ankle is farther from the hip or point of
attachment compared to the elbow)
10. Superficial (external)
= toward or at the body surface; OUTER
11. Deep (internal)
=Away from the body surface; INNER
2.) Regional terms = Body regions, to make it easier to find particular body parts
Anterior/ Ventral Body Landmarks
1. Cephalic [FONBON] - the head
a. Frontal - forehead
b. Orbital - eye area
c. Nasal - nose area
d. Buccal - cheek area
e. Oral - mouth area
f. Mental - chin area
2. Cervical - neck region
3. Thoracic - area between the neck and
the abdomen supported by the ribs,
sternum, and costal cartilages. [SAP]
a. Sternal - breastbone area
b. Axillary - armpit
c. Pectoral - relating to, or
occurring in or on, the chest.
4. Abdominal -anterior body trunk
inferior to the ribs
a. Umbilical- navel
5. Pelvic - the area overlying the pelvis
anteriorly
7. Upper Limb
a. Acromial - point of the
shoulder
b. Deltoid - curve of the shoulder
formed by large deltoid
muscle.
c. Brachial - arm
d. Antecubital - anterior surface
of the elbow
e. Antebrachial - forearm
f. Carpal - wrist
8. Manus (hand)
a. Digital - fingers
-------------------------------------------------Posterior/Dorsal Body Landmarks
1. Cephalic
a. Occipital (back of the head)posterior surface of the head;
base of the skull.
2. Cervical - posterior part of the neck
region
3. Back (Dorsal)
a. Scapular
b. Vertebral
c. Lumbar
d. Sacral
e. Gluteal
4. Upper Limb
a. Acromial - points of the
shoulder
a. Inguinal (groin) area where
the thigh meets the body
trunk
6. Pubic (genital)
9. Lower Limb
a. Coxal - hip
b. Femoral - thigh - applies to
both the anterior and
posterior
c. Patellar - anterior knee
d. Crural (leg) - anterior leg or
the the shin
e. Fibular- lateral part of the leg
10. Pedal (foot)
a. Tarsal - ankle
b. Digital - toes
b. Brachial - arms
c. Olecranal - posterior surface
of the elbow
d. Antebrachial - forearm
5. Manus - hand
a. Digital - fingers
6. Lower Limb
a. Femoral - thigh
b. Popliteal - posterior knee area
c. Sural (calf) - posterior surface
of the leg
d. Fibular - lateral part of the leg
7. Pedal - foot
a. Calcaneal - heel of the foot
b. Plantar - sole the foot actually
on the inferior body surface
3) Body plane and sections = Sections are cuts along imaginary lines known as planes.The types
exist as right angles to one another.
1. Sagittal Section = divides the body or organ into left and right parts
a. Median or Midsagittal Section = divides the body or organ into equal left or right
parts.
b. Parasagittal = all other sagittal sections. (para = near)
2. Frontal or Coronal Section = divides the body or organ into anterior and posterior parts
3. Transverse or Cross section = divides the body or organ into superior and inferior parts
4) Body Cavities= Body cavities provide varying degrees of protection to organs within them.
Internal body cavities:
1. Dorsal Cavity =two subdivisions
a. Cranial Cavity
- Houses the brain
- Protected by the skull
b. Spinal Cavity
2. Ventral Cavity = two subdivisions separated by the diaphragm; much larger than
the dorsal cavity, and contains all the structures in the chest and abdomen.
a. Thoracic Cavity
- Cavity superior to the diaphragm
- Houses the heart, trachea, and other organs
- Mediastinum => central region
- Houses the heart, aorta, esophagus, thymus, trachea, lymph
nodes and nerves.
- Separates the lungs into right and left cavities in the thoracic
cavity.
b. Abdominopelvic Cavity
- Cavity inferior to the diaphragm;
- Commonly divided into two:
1. Superior abdominal cavity
=> contains the stomach,liver, intestines, and other organs
protected only by the trunk muscles.
2. Inferior abdominal cavity
=> contains the stomach, liver, intestines, and other organs
protected
somewhat by
bony pelvis
-
-
-
No physical structure
separates abdominal
from pelvic cavities
The pelvic cavity is
not immediately
inferior to the
abdominal cavity, but
rather tips away from
the abdominal cavity
in the posterior
direction.
Sub-divided into four
quadrants are named
according to their
relative location
b.1 Abdominopelvic Cavity Quadrants = 4 quadrants
1. Right Upper Quadrant (RUQ)
- Liver, right kidney, gallbladder,portion of
the colon and the pancreas.
2. Left Upper Quadrant (LUQ)
- Stomach, left kidney, spleen, portion of the
colon and the pancreas.
3. Right Lower Quadrant (RLQ)
- Appendix, colon, small intestine ,uterus, major artery and vein to the right leg.
4. Left Lower Quadrant (LLQ)
- Colon, small intestine,major vein and artery to the left leg.
5. Midline
- Aorta, pancrea, small intestine, bladder, spine
-----------------b.2 Abdominopelvic Cavity Regions = 9 regions : H-E-L-U-I-H
1st Row
Hypochondriac Regions = flank the epigastric region and contain the lower ribs
“Chondro” = cartilage
1. Right Hypochondriac Region
- Liver, right kidney, gallbladder, large and small intestines
2. Epigastric Region
- Liver, stomach, spleen, duodenum, adrenal glands, pancreas
- Located superior to the umbilical region (“Epi-”=upon; above)
(“gastric”=stomach)
3. Left Hypochondriac Region
- Liver’s lip,stomach, pancreas, left kidney, spleen, large and small intestine.
-----------2nd Row
Lumbar Regions = lie lateral to the umbilical
region ( “lumbus” = loins) and;
= spinal column between the
bottom ribs and the hip bones
4. Right Lumbar Region
- Ascending colon, small intestine,
right kidney
5. Umbilical Region
- Duodenum, small intestine,
transverse colon
- Centermost region, deep to and
surrounding the umbilicus
(navel).
6. Left Lumbar Region
- Descending colon, small
intestine, left kidney
----------3rd Row
Iliac Region = are lateral to the hypogastric region (“iliac”= superior part of the hip bone)
7. Right Iliac Region (Inguinal Region)
- Appendix, cecum, ascending colon, and small intestine
8. Hypogastric Region (Pubic Region)
- Bladder, sigmoid colon, small intestine, reproductive organs
- Inferior to the umbilical (“Hypo-” = below)
9. Left Iliac Region (Inguinal Region)
- Sigmoid colon, descending colon, small intestine.
b.3 Other Body Cavities = most are in the head and open to the body exterior, except for the oral
and digestive cavities.
● Oral and Digestive Cavities
- Teeth and tongue
- Part of and continuous of the digestive organs, which open at the exterior of the
anus
●
●
●
Nasal Cavity
- Located within and posterior to the nose
- Part of the respiratory system
Orbital Cavity
- “Orbits” in the skull
- House the eyes and present them in an anterior position
Middle Ear Cavities
- Cavities into the skull and lie medial to the eardrums
- Tiny bones that transmit sound vibrations to the hearing receptors in the inner ears.
Homeostasis
-
-
Maintenance of relatively stable internal conditions
A dynamis state of equilibrium, or balance
Necessary for normal body functioning and to sustain life
Main Controlling Systems:
- Nervous system
- Endocrine System
Homeostasis Imbalance
- A disturbance in homeostasis results in disease
Maintaining Homeostasis = All homeostasis control mechanisms have at least three compounds:
1. Receptor
- Responds to changes in environment (stimulus/stimuli)
- Sends information to the control center along an afferent pathway
- AAAfferent = AAApproaching
2. Control Center
- Determines set point; ex. Body Temperature = 37 degrees Celsius
- Analyzes; Information
- Determines appropriate response
3. Effector
- Gland, organs or system that will administer the response from the brain or control
center.
- Provides a means for response to the stimulus
- Information flows from control center to effector along efferent pathway
- EEEfferent = EEEffect
Feedback homeostatic mechanism
● Negative feedback
- Counter-action
- Includes most homeostatic control mechanisms
- Shuts off the original stimulus or reduces its intensity
- Works like a household thermostat = the thermostat contains both the receptor and
the control center.
If the thermostat is set at 20℃ (68℉), the heating system (effector) will be
triggered ON when the house temperature drops below 20℃
- As furnace produces heat, the air is warmed,
- The furnace will shut OFF if the thermostat sends a signal implying that the
temperature reaches 20℃ or slightly higher.
●
Positive feedback
- Rare homeostatic control mechanisms
- Increases the original stimulus to push the variable further
- Reaction occurs at faster rate
- In the body, positive feedback occurs in blood clotting and during the birth of a baby
II. Cells and Tissues
Cells
- 1600
Robert Hooke = He looked through a crude microscope at some plant tissue- cork
= He saw cubelike structures that reminded him of long rows of
monk’s room. He called them “cells”
- 1800
-
Cell theory
= Basic building blocks of life
= The activity of an organism depends on the collective activities of its cells.
= Principle of complementarity - the activities of cells are dictated by their
structure(anatomy), which determines function (physiology).
=Continuity of life has cellular basis
Contains all the necessary parts to survive in a changing world.
Loss of cell homeostasis underlies virtually every disease.
Every living contains 60% water; water is essential for life
Anatomy of a Generalized cell
Three main regions of the generalized cell:
- Nucleus -located near the center of the cell
- Plasma Membrane - the outer cell boundary
that encloses the cell
- Cytoplasm - organelles within the cell are
surrounded by the semifluid cytoplasm
1. Nucleus
= “headquarters of the cell”or control
center
= “nucle” = kernel
= Contains the genetic material or
deoxyribonucleic acid (DNA)
- Blueprint; contain all
instructions needed for building
the whole body
- Has genes, which carries
instructions for building proteins
- Important for cell reproduction
= Lost or ejected nucleus = selfdestruction of cell
= The shape is most often oval or
spherical (sometimes it depends on the shape of
the actual cell)
= Has three structures or regions: (1) nuclear envelope, (2) nucleolus, and (3) chromatin
a. Nuclear Envelope = double membrane barrier / nuclear membrane
- Fluid-filled “moat”, or space is found between the two membrane
- Nuclear Pores - the two layers of the nuclear envelope fused creating an
opening (the nuclear pores).
- Allows some substances but not all substances to pass through the cell.
- It encloses a jelly-like fluid called “nucleoplasm”, in which other nuclear
elements are suspended.
b. Nucleolus = contains nucleoli [Nucleolus (Singular) / Nuclei (Plural)]
- Nucleoli = one or more small, dark-staining, essentially round bodies
= little nuclei
=Sites for ribosomes (cell structures) to assemble
=> Ribosomes eventually migrate into cytoplasm = actual
sites of protein synthesis
2.
c. Chromatin
When the cell is NOT dividing....
- Histones = proteins that are wound carefully by DNA
= used to form chromatin
- Chromatin = A loose network of “beads on a string” formed by histones
- Scattered throughout the nucleus
When the cell IS dividing....
- ...to form daughter cells => Chromosomes = “chromo”= colored;
“soma”=body
- Chromosomes = chromatin threads coiled and condensed to rod like bodies.
Plasma Membrane
- Cell’s surface or outer limiting membrane
- A fragile transparent barrier that contains the cell contents (separates the cell contents
from the surrounding environment)
- Important in defining the limits of the cell
- Much more than a passive envelope
- Allows organelles to maintain an internal environment
A.
The Fluid Mosaic Model =The structure of the plasma membrane consists of two
phospholipid (fat) layers arranged “tail to tail” with cholesterol and floating proteins
scattered among them.
The
proteins, some of which are free to move and bob in the lipid layer, form a constantly
changing pattern or mosaic, hence the name of the model that describes the plasma
membrane.
1. Phospholipid bilayer = forms the
basic “fabric of the membrane”
2. Hydrophilic = “hydro”= water;
“phillic”=love
= Polar “heads” of the lollipopshaped phospholipid molecules
= “water loving” and are
attracted to water.
= Main component of both the
intracellular and extracellular
fluids
3. Hydrophobic = “hydro”=water;
“phobic”=fear
= Non-polar fatty acid “tails” are hydrophobic
=”water-fearing”, avoids water
= lines up in the center (interior) of the membrane.
= makes the plasma membrane relatively impermeable to most water-soluble molecules.
4. Cholesterol = helps both stabilize the membrane and keep it flexible.
5. Proteins = scattered in the lipid bilayer
= are responsible for most specialized functions of the membrane.
= Some are enzymes
> Proteins protruding from the cell:
- Receptors for hormone
- Chemical messengers
- Binding sites for anchoring the cell to fibers or to other structures inside or outside
the cell
> Proteins that span the membrane
- Involved in transport.
*Some proteins cluster to form protein-channels (tiny pores) through which water and small
water-soluble molecules or ions can move
* Others act as carriers that bind to a substance and move it through the membrane.
Sugar Groups “Glyco”= sugar
6. Glycoproteins = “sugar proteins” = branching sugar groups are attached to most of the
proteins abutting the extracellular space.
= determines your blood type
=acts as receptors that certain bacteria,viruses, or toxins can bind to
=plays a role in cell-to-cell recognition
7. Glycocalyx = the cell surface which is a fuzzy, sticky, sugar-riched area
8. Glycolipid = formed from sugar groups attached to phospholipids
B. Cell Membrane Junctions
- Cells are bound together in three ways
> Glycoproteins in the glycocalyx acts as an adhesive or cellular glue.
> Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove
fashion
> Special cell membrane junctions are formed. Varied structurally depending on their roles.
- Types of Junctions:
a. Tight Junctions =
impermeable junctions
= encircles the cells
=binds them together into
leak proof sheets
= Like a zipper = adjacent
plasma membrane fused
together tightly
- To prevent substances
from passing through
b. Desmosomes = anchoring
junctions
=scattered like rivets along
the sides of adjacent cells
=prevents cells subjected to mechanical stress (heart muscle cells and skin cells)
from being pulled apart.
= Buttonlike thickenings of adjacent plasma membranes (plaque)
= Connected by fine protein filaments
= Internal system of strong “guy wires” - formed by thicker protein filaments
extended from the plaques inside the cells to the plaques on the cells’ opposite side.
c. Gap Junctions = communicating junctions
= Allow communication between neighboring cells
= Neighboring cells are connected by connexons. And allows chemical molecules
(nutrients or ions) to pass directly through water-filled connexon channels from
one cell to another.
(Connexons = hollow cylinders composed of proteins)
= Transmembrane Proteins = connexons spanning the entire width of the abutting
membranes.
3. Cytoplasm
- Cellular material outside the nucleus and inside the plasma membrane.
- Site of most cellular activities
- “Factory floor” of the cell.
- Structureless gel
- Three major components: (1) cytosols, (2) inclusions and (3) organelles
1. Cytosols = semi transparent fluid that suspends the other elements.
= Nutrients and a variety of solutes are dissolved in the cytosol.
2. Inclusions = chemical substances that may or may not be present, depending on the specific
cell type.
=Most are stored nutrients or cell products floating in cytosol
= Include liquid droplets common in fat cells, glycogen granules abundant in liver and
muscles, and pigments
= A cellular “pantry” = items are kept on hand until needed
3. Organelles =specialized cellular compartments = metabolic machinery of the cell
=Each type of organelle carries a specialized function.
a. Mitochondria (plural) / Mitochondrion (singular)
- tiny , lozenge-like or sausage-shaped organelles
- Supplies most of the ATP = Powerhouse of the cell
- Double membrane , equal to two plasma membranes placed side by side.
- Enzymes dissolved
in the fluid of the
mitochondria
- Outer Membrane
= smooth and
featureless
- Inner membrane
-
= shelflike protrusions called “cristae”
Enzymes that also form part of the cristae = carries reactions in
which oxygen breaks down foods
- ATP (Adenosine Triphosphate) = energy
released from breaking down food
= provides the energy for all cellular work and
every living ( cells need energy/ATP )
b. Ribosomes = tiny bilobed, dark
bodies made of proteins and
one variety of RNA called
ribosomal RNA.
= Actual sites of protein
synthesis
= Roams freely in the cytoplasm
= Some are attached to membranes i.e. rough ER (which produces proteins that
function outside the cell
c. Endoplasmic Reticulum (ER) = “network within the cytoplasm”
= a system of fluid-filled tunnels that coil and twist through the cytoplasm.
= Cell’s mini-circulatory system
=it provides a network of channels for carrying substances (mostly protein)
= Two forms of ER:
- Rough endoplasmic reticulum = rough because it is studded with ribosomes
- Cell membrane’s factory.
- Proteins made on its ribosomes migrate into the rough ER tunnels.
Where they fold into their functional 3D shapes.
- Transport vesicles = proteins are dispatched to other areas of the
cell in small “sacs” of membrane.
= carry substances around the cell.
- Especially abundant in cells that make (synthesize) and export
(secrete) proteins
- Enzymes that catalyze the synthesis of membrane lipids reside on
the external (cytoplasmic) face of the rough ER, where the needed
building blocks are readily available.
- Smooth endoplasmic reticulum = communicates with the rough ER.
- Plays no role in protein synthesis
- Lacks the ribosomes
- Functions in lipid metabolism (cholesterol and fat synthesis and
breakdown)
- Functions in detoxification of drugs and pesticides
- Liver cells are chock-full of smooth ER
c. Golgi Apparatus = appears as a stack of flattened membranous sacs that are
associated with swarms of tiny vesicles.
- Found near the ER.
- Principal “Traffic Director” for cellular proteins
- Major function = modify, package and ship proteins (sent by rough ER via
transport vesicles
d. Lysosomes = membranous “bags” containing powerful digestive enzymes
e. Peroxisomes = “peroxide bodies” ; are membranous sacs containing powerful
oxidase ; main function = “disarm” dangerous free radicals.
Free radicals = are highly reactive chemicals with unpaired electrons that
can damage the structure of proteins and nucleic acids.
f. Cytoskeleton = an elaborate network of protein structures extends throughout the
cytoplasm.
- Acts as cell’s “bones and muscles” by furnishing an internal framework that
determines the cell shape; supports other organelles, and provides the
machinery for intracellular transport.
-
Made up of microfilaments, intermediate filaments, and microtubules
g. C
e
n
t
r
i
o
l
e
s
=
p
a
i
r
e
d
centrioles collectively are called centrosomes.
- Lies close to the nucleus
- Generates microtubules
- Directing the formation of the mitotic spindle during cell division
h. Cilia = whiplike cellular extensions that move substances along the surface of the
cell.
i. Flagella = long projections formed by the centrioles
j. Microvilli = tiny, fingerlike extensions of the plasma membrane that projects from
an exposed cell surface
Cell
Dive
rsity
Ther
e are
200
diffe
rent
cells
They
vary
in
size,
shape
, and
functi
on.
1. S
p
h
e
r
e
s
h
a
p
e
f
a
t
c
e
l
l
s,
2. Disc-shaped red blood cells
3. Branching nerve cells
4. Cube shaped cells of kidney tubules
-Length-ranging from 1/12,000 of an inch in the smallest cells to over a yard
-Shape reflects its function
1.
2.
3.
4.
5.
6.
Cell that connects that body parts
Cells that cover and line Body Organs
Cells that move Organs and Body Parts
Cell Diversity
Cell that Gathers Information and controls body function
Cell for Reproduction
Cell Physiology
= Ability to metabolize (use nutrients to build new cell materials, breakdown substances and make
ATP
= Digest food
=Dispose waste
=Reproduce, grow, move and respond to stimulus
Membrane Transport
+ Solution = a homogeneous mixture of two or more components.
- Solvent = the largest amount in a solution
- Solute = components or substances present in smaller amounts
+ Intracellular fluid (collectively, the nucleoplasm and the cytosol) = solution containing
small amounts of gases(oxygen, and carbon dioxide) nutrients, and salts dissolved in water
+ Extracellular fluid or Interstitial fluid = continuously bathes the exterior of our cells.
+ Selective Permeability = means that a barrier allows some substances to pass through it
while excluding others. Allows only nutrients to go in the cell.
>Passive Processes: Doesn’t need ATP (or energy) to move substances
1. Diffusion = an important means of passive membrane transport for every cell of the body
- Process by which molecules (and ions) move away from areas where they are more
concentrated to areas where they are are less concentrated
- Substances move down the concentration gradients. Concentration gradient= when
the concentration of particles is higher in one area than the other.
- The greater the difference in concentration between the two areas, the faster the
diffusion occurs.
- The speed of diffusion is affected by the size of the molecules
- The hydrophobic core of the plasma membrane is a physical barrier to diffusion.
- Molecules will diffuse through plasma membrane if :
-
The molecules are small enough to pass thru the membrane’s pores
(channels formed by membrane proteins)
The molecules are lipid-soluble
The molecules are assisted by a membrane
Simpl
e
Diffu
sion
=
The
unass
isted
diffus
ion of
solut
es
throu
gh
the
plas
ma
membrane ( or any selectively permeable membrane.
- Osmosis = diffusion of water through a selectively permeable membrane such as the plasma
membrane.
= water is highly polar, it is repelled by (non-polar) lipid core of the plasma membrane
= but it can and does pass easily through special pores called “Aquaporins”
- Facilitated diffusion= driven by the kinetic energy of molecules= provides passage for certain
needed substances (notably glucose) that are both lipid-insoluble and too large to pass through the
membrane pores, or charged, as in the case of chloride ions passing through a membrane protein
channel.
2. Filtration= generally occurs only across capillary walls
process by which water and solutes are forced through a membrane (or capillary
wall) by fluid, or hydrostatic, pressure.
- A passive process, and a pressure gradient is involved. Pressure Gradient= pushes
solute-containing fluid (filtrate) from the higher-pressure area through the filter to
the lower-pressure area.
- Only blood cells and protein molecules too large to pass through the membrane
pores are held back
Cellular Tonics
1. Isotonic = have the same solute and water concentration (“Iso”= equal; “Tonic” = a
physiological response which is slow and may be graded. Result: Cell EQUAL
= Higher concentration of solutes outside the cell than inside the cell.
=When a cell is immersed into a hypertonic
2. Hypertonic= a solution that contains more solutes, or dissolved substances than there are
inside the cell. From lower to higher concentration. Dehydrates the cell. The solution will
push excess fluid out of the cell Result: Cell SHRINKS
3. Hypotonic= a solution containing fewer solutes (more water)
than the cell does. Hydrates the cell. Result: Cell BURST
> Active Processes: Whenever a cell uses ATP to move substances across the membrane
1. Active transport = require protein carriers that interact specifically and reversibly with the
substances to be transported across the membrane.
- Uses ATP to energize its solute pumps (protein carriers)
- Solute pumps transport amino acids, some sugars and most ions.
- The substances move against the concentration (or electrical) gradients.
Sodium-potassium ( Na+ -K+) pump = alternately carries sodium ions (Na+) out of and potassium
ions (K+) into the cell.
- Having this process is absolutely necessary for normal transmission of nerve impulses.
- There are more sodium ions outside the cells than inside, so those inside tend to remain in
the cells than inside, so those inside tend to remain in the cell unless the cells use ATP to
force, or “pump”, them out.
- ATP is split into ADP and P (inorganic phosphate), and the phosphate is then attached to the
sodium-potassium pump in a process called phosphorylation. Likewise, there are more
potassium ions inside cells than in the extracellular fluid, and potassium ions that leak out
of cells must be actively pumped back inside.
- Because each of the pumps in the plasma membrane transports only specific substances,
active transport provides a way for the cell to be very selective in cases where substances
cannot pass by diffusion. (No pump-no transport).
Vesicular Transport
-
-
Involves help from ATP to fuse or separate membrane vesicles and the cell membrane,
moves substances into or out of the cells “in bulk” without their actually crossing the plasma
membrane directly.
Two types: Exocytosis and Endocytosis
1. Exocytosis (Out of the cell) = the mechanism that cells use to actively secrete
hormones, mucus, and other cell products or eject certain cellular wastes.
= The product to be released is first “packaged” (typically by the Golgi apparatus)
into a secretory vesicle.
=Vesicle migrates to the plasma membrane, fuses with it, and then ruptures, spilling
its contents out of cell
= involves a “docking” process in which docking proteins on the vesicles recognize
plasma membrane docking proteins and bind with them. This binding causes the
membranes to “cork-screw” together and fuse.
2. Endocytosis (Into the cell) =includes those ATP-requiring processes that take up, or
engulf, extracellular substances by enclosing them in a vesicle.
=Once the vesicle is formed, it detaches from the plasma membrane and moves into
cytoplasm, where it typically fuses with a lysosome and its contents are digested (by
lysosomal enzymes). However in some cases, the vesicle travels to the opposite side
of the cell and releases its contents exocytosis there.
a. Phagocytosis = the engulfed substances are relatively large particles, such
as bacteria or dead body cells, and the cell separates them from the external
environment by pseudopods. PHAGOCYTOSIS= “Cell eating”
= White blood cells (macrophage), and other phagocytes of the body act as
the scavenger cells that police and protect the body by ingesting bacteria
and other forgein debris
= Protective mechanism - a way to “clean house”- not a means of getting
nutrients
b. Pinocytosis =Cells eat by phagocytosis and drink by a form of endocytosis,
during which the cell “gulps” droplets of extracellular fluid.
=Plasma Membrane indents to form a tiny pit or “cup” , and then its edges
fuse around the droplet of extracellular fluid containing dissolved proteins
or fats.
= A routine activity of most cells that function in absorption (for example,
cells forming the lining of the small intestine)
c. Receptor-mediated endocytosis =main cellular mechanism for taking up
specific target molecules.
=In this process, receptor proteins on plasma membranes bind exclusively
with certain substances.
=Both the receptors and high concentrations of the attached target
molecules are internalized in a vesicle, and then the contents of the vesicle
are dealt with in one of the ways.
= Although phagocytosis and pinocytosis are important, they are not very
selective compared to receptor-mediated endocytosis including enzymes,
some hormones, cholesterol, and iron.
= Unfortunately, flu viruses exploit this route to enter and attack our cells.
Cell life cycle = is the series of changes a cell goes through from the time it is
formed until it divides.
=The cycle has two major periods:
a. Interphase = in which the cell
grows and carries on its usual
metabolic activities,
= the longer phase of the cell
cycle, the cell is very active
and is preparing for cell
division.
= Metabolic phase.
b. Cell division = during which it
reproduces itself.
Preparations: DNA Replication
= function of cell division is to
produce more cells for growth and
repair processes.
= the important event always
precedes cell division: The DNA
molecule (the genetic material) is
duplicated exactly in a process.
= This occurs toward the end of
interphase.
Precise trigger for DNA synthesis
= The process begins as the DNA helix
“unzips”, gradually separating into its
two nucleotide chains.
= Each nucleotide strand then serves
as a template, or set of instructions.
Adenine (A) = always bonds to
Thymine (T)
Guanine (G) = always bonds to
Cytosine (C )
The order of the nucleotides on the
template strand also determines the
order on the new strand with the order ATG ACG.
The end result is two DNA molecules that are identical to original DNA helix,
Each consists one of old and one newly assembled nucleotide strand.
Events
of Cell
Division
Mitosis, or division of the cytoplasm; cytokinesis which begins when mitosis is nearly
completed .
Mitosis = process of dividing a nucleus into two daughter nuclei with exactly the same genes
as the “mother” nucleus.
= DNA replication precedes mitosis, so that for a short time the cell nucleus contains a
double dose of genes.
=when the nucleus divides, toward opposite sides of the cell, directing the assembly
of a mitotic spindle (composed of microtubules)
- Mitotic Spindle = composed of microtubules between them as they move. The
spindle provides scaffolding for the attachment and movement of the
chromosomes during the later mitotic stages.
= same in all animal cells
By the end of prophase, the nuclear envelope and the nucleoli have broken down
And temporarily disappeared, and the chromosomes have attached
randomly to the
spindle fibers by their centromeres.
A. Metaphase
= (short stage) the chromosomes line up at the metaphase plate (center of the
spindle midway between centrioles) so that a straight line of chromosomes is seen.
B. Anaphase
= the centromeres that have held the chromatids (chromosomes) begin to move
slowly apart, drawn toward opposite ends of the cell.
=Chromosomes seem to be pulled by their half-centromere, with their “arms”
dangling behind them.
= This careful division of sister chromatids ensures that each daughter cell gets one
copy of every chromosome.
= Anaphase is over when the chromosomes stop moving.
C. Telophase
= essentially prophase in reverse.
=The chromosomes at opposite ends of the cell uncoil to become threadlike
chromatic again.
=The spindle breaks down and disappears, a nuclear envelope forms around each
chromatin mass, and nucleoli appear in each of the daughter nuclei.
*Mitosis is similar in all animal cells. Depending on the type of tissue, it takes from 5 minutes to
several hours to complete, but typically it lasts about 2 hours.
*Centriole replication is deferred until late interphase of the next cell cycle, when DNA replication
begins before the onset of mitosis.
Cytokinesis = division of the cytoplasm, usually begins during late anaphase and completes during
telophase.
= A contractile ring made of microfilaments forms a cleavage furrow over the midline of the
spindle, and it eventually squeezes, or pinches, the original cytoplasmic mass into two parts.
=The end of cell division, two daughter cells exist.
= Each is smaller with less cytoplasm than the mother cell had but is genetically identical to the
mother cell.
=The daughter cells grow and carry out normal cell activities (interphase) until it is their turn to
divide.
*Mitosis and cytokinesis usually go hand in hand, but in some cases the cytoplasm is not divided.
This condition leads to formation of binucleate (two nuclei) or multinucleate cells.
Protein Synthesis
-
Key substances for all aspects of cell life
a. Fibrous (structural) proteins = major building materials for cells
b. Globular (functional) proteins = perform functional roles in the body
-
All enzymes, biological catalysts that speed up every chemical reaction that occurs in cells,
are functional proteins.
It follows, then, that every cell needs to produce proteins, a process called “ Protein
Synthesis”.
This is accomplished with the DNA blueprints known as genes and with the help of the
nucleic acid RNA.
Gene: The Blueprint for Protein Structure
DNA = serves as the master blueprint for protein synthesis.
Gene = defined as a DNA segment that carries the information for building one protein.
DNA’s information = encoded in the sequence of bases.
Each sequence of three bases calls for a particular amino acid
*Amino acids are the building blocks of proteins and are joined during protein synthesis.
*For example, a DNA base sequence of AAA specifies an amino acid called “Phenylalanine”.
CCT calls for glycine.
* Just as different arrangements of notes on sheet music are played as different chords,
variations in the arrangements A,C,T and G in each gene allow cells to make all the different kinds of
proteins needed. A single gene contains an estimated 300 to 3,000 base pairs in sequence.
The Role of RNA
- DNA is a coded message; information is not useful until it is decoded.
- Most ribosomes; the manufacturing sites for proteins -are in the cytoplasm, but DNA
never leaves the nucleus during interphase.
- DNA requires not only a decoder but also a trusted messenger to carry the
instructions for building proteins to the ribosomes.
- These messenger and decoder functions are carried out by a second type of nucleic
acid, ribonucleic acid, or RNA.
RNA differs from DNA in being single-stranded, in having ribose sugar instead of deoxyribose, and
in having a uracil (U) base instead of thymine (T)
Three varieties of RNA play a special role in protein synthesis.
1. Ribosomal RNA (rRNA) helps form the ribosomes, where proteins are built.
2. Messenger RNA (mRNA) molecules are long, single nucleotide strands that resemble half of
a DNA molecule. They carry the “message” containing instructions for protein synthesis
from the DNA (gene) in the nucleus to the ribosomes in the cytoplasm.
3. Transfer RNA (tRNA) molecules are small, cloverleaf-shaped molecules that escort amino
acids to the ribosome.
The Process of Protein Synthesis
1. Transcription = complementary mRNA (the messenger) is made using the information in
the DNA gene
= refers to one of the jobs done by the secretary : converting notes from one form into
another form.
= Transfer of information from the sequence of bases in a DNA gene into the
complementary sequence by an enzyme.
=DNA is the template for transcription;
and mRNA is the product
= Triplet: each three-base sequence specifying a particular amino acid on the DNA gene.
= Codons: the corresponding three-base sequences on mRNA.
= The form is different, but the same information is being conveyed.
If the (partial) sequence of DNA triplets is
AAT-CGT-TCG, RNA base-pairing rules
(A:U, G:C) tell us that the corresponding
codons on mRNA would be UUA-GCAAGC.
2. Translation = when the information
carried in mRNA molecules is “decoded”
and translated from nucleic acids into
proteins.
= A translator takes words in one
language and restates them in another
language.
= the language of nucleic acids (base
sequence) is “translated” into the
language of proteins (amino acid
sequence).
= Occurs in the cytoplasm and involves
three major varieties of RNA.
= Consists of the following series of events:
(1) --(2) mRNA
(3) tRNA transfers, or delivers, amino
acids to the ribosome
- Where they are linked
together by peptide bonds
(formed by dehydration
synthesis) in the exact
sequence specified by the
gene (and its mRNA).
- There are about 45 common
types of tRNAs, each capable
-
-
of carrying one of the 20 types of amino acids.
They have to recognize the mRNA codons to “double check” that the amino
acid they are toting will be added in the correct order.
They can do this because they have a special three-base sequence called an
“Anticodon” on their “head” that can temporarily bind to the complementary
codons
tRNA has maneuvered itself into the correct position at the beginning of the
mRNA message, the ribosome moves the mRNA strand along, bringing the
next codon into position to be read by another tRNA.
Histology : Tissues
- Group of cells that are similar in structure function
- Organized into organs
- Most of organs contains several tissues types, and the arrangement of the tissue
determines each organ’s structure and its functions
Body Tissues:
Tissues: Group of cells that are similar in structure and functions; represents structural
organization.
Functions of Tissues:
a. Covering = epithelium
b. Support = connective
c. Movement = muscle
d. Control = nervous
Four Types of Body Tissues
1. Epithelial Tissue (Epithelium) - Lines cavities and surfaces of blood vessels and organs
throughout the body.
- Epithe = laid on, covering. Plural form: Epithelia.
- Lining, covering and glandular tissue
- Functions: protection, absorption filtration, and secretion.
General Classification:
● Covering or Lining Tissue
- Cells can be stratified (layered), ciliated or keratinized
● Glandular or Secretory Tissue
- Cells are specialized to secrete materials such as digestive tissues,
hormones, milk, sweat, and wax.
● Endocrine Glands Cells
- Form ductless glands that secrete substance directly into the
bloodstream
- E.g. thyroid gland and adrenal gland
● Exocrine Gland Cells
- Secrete substances into ducts
- E.g. Mammary glands, sweat glands, and salivary glands.
Characteristics of Epithelial Tissue
● Cellularity - composed almost entirely of cells
● Special Contacts - forms continuous sheets held together by tight junctions and
desmosomes
● Supported by Connective tissue - reticular and nasal laminae
● Regenerative - rapidly replaces lost cells by cell division
Classification of Epithelia
1. Based on the number of cell layers
a. Stratified - more than one
layer
- Cells at free surface
2. Based on the cell shape
- “Squished”
a. Squamous - flattened
b. Cuboidal - cube-shaped
c. Columnar - columns
b. Simple - one layer
3. Function of epithelial tissue related to tissue type
Simple Epithelia
- Very thin
- Absorption, secretion and filtration
Simple
Squamous
Epithelium
*Single Layer of squamous
cells
*Filtration or exchanges of
substances by rapid
diffusion
* Also forms “Serous
membranes” = slick
membranes that line the
ventral body cavity and
cover the organs in that
cavity
Description: Single layer of
flattened cells with discshaped central nuclei and
sparse cytoplasm; the
simplest epithelia
Function: Allows materials
to pass by diffusion and
flitration in sites where
protection is not important;
secretes lubricating
substances in serosae.
Location: Kidney glomeruli;
air sacs of lungs; lining of
heart, blood vessels, and
lympathic vessels; lining of
ventral body cavity
(serosae).
Simple Cuboidal
Epithelium
* One layer of cuboidal cells
* Common in glands and
their associated small tubes
called ducts.
* Also forms the walls of the
kidney tubules and covers
the surface of the ovaries
Simple Columnar
Epithelium
* Single layer of tall cells
*Goblet cells = produce a
lubricating mucus
*Lines the entire length of
the digestive tract from the
stomach to the anus.
* Mucosae/ Mucous
membranes = Epithelial
membranes that line body
cavities open to the body
exterior.
Pseudostratified
Columnar
Epithelium
*False stratified. Actually
Simple
* Absorption and secretion
* Pseudostratified ciliated
columnar epithelium = lines
most of the respiratory tract
Stratified Epithelia
- Consists of two or more cell layers
-
More durable than simple epithelia
Protection
Stratified
Squamouse
Epithelium
* Most common stratified
epithelium in the body
* Consists of many layers
*Found in sites that receive a
good deal of abuse or friction,
*E.g. Surface of the skin, the
mouth, and the esophagus.
Stratified
Cuboidal
Epithelium
*Two cell layers
*Extremely limited
Stratified
Columnar
Epithelium
*Columnar cells
*Basal cells vary in size and
shape
Transitional
Epithelium
*Highly modified
*Stratified squamous epithelium
= forms the lining of only a few
organs
* E.g. Urinary bladder, ureters
and part of the urethra. ~ all of
these organs are subject to
stretch.
*Ability: to slide past one
another and change their shappe
*E.g. Allows the ureter wall to
stretch as a greater volume of
urine flows.
2. Connective Tissue
- Connects body parts
- Most abundant wide distributed
- Function: protection, support and bind together other body tissues
Characteristics of connective tissue
● Variations in blood supply
○ Connective tissues are well vascularized
○ Tendons and ligaments = poor blood supply
○ Cartilages = avascular
○ All these structures heal very slowly when injured
● Extracellular Matrix
○ Produced by connective tissue cells
○ Secreted to the exterior
■ Ground substance
■ Fibers ;
Body Membranes
- Line Body Cavities
- Cover Body surfaces
- Protect body surfaces
- Lubricate body surfaces
2 Major Groups of Body Membranes
1. Epithelial Membranes = “covering and lining membranes “
a. Cutaneous membrane (skin or integumentary system)
- Expose to air and a dry membrane
- Outermost protective boundary
i.
Superficial epidermis = Composed of Keratinized Stratified squamous
epithelium
ii.
Underlying dermis = Mostly dense (fibrous) connective tissue
b. Mucous Membrane = refers to the location of the epithelial membranes not their
cellular make up.
Composed of stratified squamous epithelium resting on the underlying
loose connective tissue lamina propria.
- Lines all body cavities that OPEN to the exterior body surface
- “Wet and moist” in all cases
- Often adapted for absorption or secretion
c. Serous Membrane (serosa)
- Surface simple squamous epithelium
- Underlying areolar connective tissue
- Lines body cavities that are CLOSED to the exterior of the body.
- Occurs in pairs: nb
- Visceral layer = cover the inner of the organ cavity .
- Parietal (wall) layer = lines specific portion outside the wall layer of
the ventral cavity; Separated by serous fluid (a thin function to avoid
friction)
2. Connective tissue membranes
-
Skeletal System - Powerpoint
Digestive system
Hepatic Portal Circulation
Heart => Blood (oxygenated blood) = > Abdominal Aorta => Digestive organs => Abdominal
blood (Blood from digestive organs, spleen and pancreas) => Hepatic Artery => liver ( 2 major
functions in HPC: (1) First Capillary bed : Processes nutrients from the blood (2) Second Capillary
bed :Remove toxins and pathogens) => inferior mesenteric ( drains blood from terminal part of
the large intestine) > Splenic vein ( drains blood from the spleen, pancreas, and the left side of the
stomach) > Superior mesenteric ( drains blood from the small intestine and the first part of the
colon) > Left gastric vein (drains the right side of the stomach) => Hepatic portal vein => Inferior
Vena Cava => Heart