HUMAN ANATOMY / Lesson 1
THE HUMAN ORGANISM
ANATOMY VS. PHYSIOLOGY
Anatomy
• Anatomy refers to the internal and external
structures of the body and their physical
relationships
Physiology
• Physiology refers to the study of the functions of
those structures
STRUCTURAL ORGANIZATION OF THE
HUMAN BODY
Molecular Level, Cellular Level, Tissue Level,
Organism Level, Organ System, Level Organ
Level
CHARACTERISTICS OF LIFE
• All living things contain cells
• All living things contain DNA
• All living things obtain and use energy
• All living things reproduce
• All living things respond to stimuli
• All living things maintain an internal
balance
• All living things grow and develop
A 1. The basic unit of life is cell.
D 2. Hydra produce their offspring through
budding.
E 3. A dog is salivating at the smell of food.
B 4. Identical twins have 99.9% similar genes.
F 5. When you are too warm, you sweat to release
heat.
C 6. Green plants produced their food through
photosynthesis.
ANATOMICAL POSITION
• describing any orientation, location,
movement, and direction
Body Planes – imaginary planes that intersect the
body
• Mid-sagittal / Median
• Sagittal
• Frontal
• Transverse
ANATOMICAL REGIONS
Main body regions: head, neck, thorax, abdomen,
pelvis, upper and lower extremities
DIRECTIONAL TERMS
VENTRAL – towards the front of the body
DORSAL – towards the back of the body
DISTAL – away from the trunk
PROXIMAL – towards the trunk
MEDIAN – midline of the body
MEDIAL – towards the median
LATERAL – away from median
SUPERIOR – towards the top of the head
INFERIOR – towards the feet
NOTE: When you feel hyperacidity, taking an
antacid such as Kremil S® can neutralize the
stomach acidity and makes you feel better
ORGANIC COMPOUNDS
They are macromolecules composed of many
subunits such as simple sugar (carbohydrate),
glycerol and fatty acids (lipid), nucleotide (nucleic
acid) and amino acid (protein).
• These subunits are being joined together through
the process of dehydration synthesis and broken
down into simpler units in the process of
hydrolysis.
CHEMICAL BASIS OF LIFE
Differentiating
Organic
to
Compounds
Inorganic
Molecule is the basic particle of a compound that
formed when two or more atoms chemically
combine.
INORGANIC COMPOUNDS
WATER
• The most abundant compound on Earth:
transparent, odorless, incompressible liquid
• In organisms, comprises 60% to 90% of the total
chemical composition of the cells.
• Properties of water: polarity, capillary action,
density
Polarity
• responsible for effectively dissolving other polar
molecules, such as sugars and salt.
Capillary action
• refers to the ability of the liquid to rise in narrow
tubes due to cohesion and adhesion of liquid
molecules.
Density
• 0.999 kg/m³ density of water
BASES
• Either take up H or release hydroxide (OH) ions.
• Taste bitter, feel slippery or soapy and change
red litmus paper to blue. • Ammonia, antacids,
milk of magnesia, detergents, soap, and shampoos.
ACIDS
• Substances that increase H atoms greatly when
they dissociate when added to water. • Taste sour
and change blue litmus paper to red. • Common
acids include citric acid and ascorbic acid (from
citrus fruits), carbonic acid (found in soft drinks)
and acetic acid (vinegar).
• Acids and bases neutralize each other.
HCl (acid) + NaOH (base) H2O (water) + NaCl
(salt)
Dehydration synthesis
Hydrolysis
Water (H2O):
What it does: It's like the body's transportation
system. It helps move important stuff around and
controls temperature.
Carbon (C):
What it does: It's the building blocks for all the
important stuff in your body.
Hydrogen (H):
What it does: It's like the glue that holds things
together in your body.
Oxygen (O2):
What it does: It helps your body create energy
from food.
Nitrogen (N2):
What it does: It's used to build the parts of your
body that do important jobs, like proteins.
Phosphorus (P):
What it does: It's needed for things that give your
body energy and carry your genetic information.
Sulfur (S):
What it does: It helps build and stabilize important
parts in your body, like proteins.
Carbon Compounds (Organic Molecules):
What they do: These are the special tools and parts
in your body that help it work, like sugars for
energy, fats for storage, and proteins for jobs.
Think of your body like a big LEGO set. These
chemicals are the basic LEGO pieces and tools
that your body uses to build and run
everything, from your muscles to your brain.
They're the essential ingredients for life!
CARBOHYDRATES
•
Composed of C, H and O with a general
formula of Cn(H2O)n.
•
Considered as a chief source of energy for
all organisms.
•
Types
of
carbohydrates:
monosaccharides, disaccharides, polysaccharides
Monosaccharides
examples: glucose, fructose, galactose
Disaccharides
examples: sucrose , lactose, maltose
Polysaccharides
examples: cellulose, chitin, starch, glycogen
Indicators are chemicals that detect the presence
of a certain compound.
Benedict’s solution reacts with MOST monoand disaccharides.
Sucrose is a notable exception!
If a detectable carbohydrate is present, then the
indicator changes color, based on how many
carbs are present.
Green → Yellow → Orange → Red
Iodine is used to detect starch, since it reacts
readily with starch, this reaction produces a
purple-black coloration.
LIPIDS
• Share a common characteristics of being
insoluble in water but soluble in
nonpolar organic solvents
• Examples: fats (saturated, unsaturated),
phospholipids, waxes, steroids
Lipids are used for four
crucial purposes:
1. Storing energy
2. Waterproof barriers
3. Chemical messengers
4. Insulation
NUCLEIC ACIDS
• Polymers made up of monomers called
nucleotide.
• Composed of three components that are
covalently
bounded together: phosphate molecule, 5-carbon
sugar (pentose) and nitrogen-containing base.
DNA
Contains all the genetic information that programs
all cellular activities and characterizes each
organism.
RNA
RNA can move around the cells of living
organisms and thus, serve as a sort of genetic
messenger, relaying the information stored in the
cell’s DNA out from the nucleus to the ribosome
where it is used to help make proteins.
PROTEINS
• Considered as the most abundant and most
complex, yet
functionally versatile among the organic
molecules.
• Made of monomers of amino acids that are
joined
together by peptide bonds formed through
dehydration
synthesis.
• There are twenty different amino acids (AA).
Protein Test Indicator
The Biuret test is used to detect protein. The test
relies on a color change to confirm the presence of
proteins. If proteins are found, the sample will turn
violet.
Essential Amino Acids:
isoleucine (iso), leucine (leu), lycine (lyn),
methionine (met), phenylalanine (phe), threonine
(thr), tryptophan (trp) and valine (val).
Non-essential Amino Acids:
alanine (ala), arginine (arg), asparagine (asn),
aspartic acid (asp), cysteine (cys), glutamic acid
(glu), glutamine (gln), glycine (gly), histidine
(his), proline (pro), serine (ser) and tyrosine (try).
Functions of Protein:
Antibodies
Enzymes
Hormones
Membrane transport proteins
Receptor proteins
Storage proteins
Structural proteins
Carbohydrates (Carbs):
Function: Carbs are like your body's fuel. They
provide quick energy, like the gas you put in a car.
Proteins:
Function: Proteins are like the workers in your
body. They do many jobs, like building and
repairing things (like muscles), helping your body
fight off diseases, and even acting as messengers.
Lipids (Fats):
Function: Lipids are like your body's storage
containers. They store extra energy, protect your
organs, and make up part of the walls of your
cells.
Nucleic Acids (DNA and RNA):
Function: Nucleic acids are like your body's
instruction manuals. DNA tells your body how to
grow and work, like a blueprint, and RNA helps
carry out those instructions.
So, in simple terms, carbs give you energy,
proteins do all the work, lipids store stuff, and
nucleic acids tell your body what to do. They're
the basic tools your body needs to function.
HUMAN ANATOMY / Lesson 2
THE CELL
CELL STRUCTURES AND FUNCTIONS
MAJOR COMPONENTS OF ALL CELLS
CELL MEMBRANE
CHROMOSOMES
CYTOPLASM
•
•
•
It prevents osmotic bursting of the cell.
It is a pathway for movement of water
and mineral salts.
Various
modifications,
such
as
lignification, for specialized functions.
NUCLEUS
Genetic Library of the Cell
Structure:
⮚
Largest cell organelle, enclosed by an
envelope of two (2) membranes that is
perforated by nuclear pores.
⮚
It contains chromatin which is the
extended form taken by chromosomes
during interphase.
CELL MEMBRANE
Structure:
• Two
layers
of lipid (bilayer)
sandwiched between two (2) protein
layers.
Functions:
• A
partially
permeable
barrier
controlling exchange between the cell
and its environment
⮚
It also contains a nucleolus.
⮚
Nuclear envelope – composed of a lipid
bilayer that separates the nuclear content
from the cytoplasm.
⮚
The
double
membrane
is
separated by approximately 50
nm.
⮚
The
outer
membrane
is
continuous with the endoplasmic
reticulum.
⮚
Nuclear pores – selective channels that
facilitates the inward and outward
movement of molecules.
⮚
Nucleoplasm – the fluid portion of the
nucleus where the genetic material is
suspended.
⮚
Membranes are lipoprotein structures (lipid +
protein), with carbohydrates (sugar) portions
attached to the external surfaces of some lipid and
protein molecules. Typically, 2–10% of the
membranes is carbohydrate.
CELL WALL
Structure:
A rigid cell wall surrounding the cell, consisting
of cellulose microfibrils running through a matrix
of other complex polysaccharides, namely
hemicellulose and pectic substances.
Functions:
• Provides mechanical support and
protection.
• It allows a pressure potential to be
developed which aids in support.
Nucleolus – a sub organelle of nucleus,
the site where the subunits of the
ribosome are assembled and include the
synthesis and maturation of ribosomal
RNA for release in the cytoplasm where
protein synthesis occurs.
⮚
DNA molecule – a long strand present in
the nucleus, which wounds around
histone proteins to form a helical
structure termed as chromatin strands.
⮚
Chromosomes – formed during cell
division by the
chromatin strands.
⮚
condensation
of
In prokaryotes, the chromosomes are
circular and no membrane enclosing the
chromosomes.
Functions:
• Chromosome contain DNA, the molecule
of inheritance.
• DNA is organized into genes which
control all the activities of the cell.
• Nuclear division is the basis of cell
replication, and hence reproduction.
• The nucleolus manufactures ribosomes.
RIBOSOMES
Protein Factories in the Cell
Structure:
• Very small organelles consisting of a
large and a small subunit.
• They are made of roughly equal parts of
protein and RNA.
• Slightly smaller ribosomes are found in
mitochondria and chloroplasts in plants.
Functions:
• Sites of protein synthesis, holding in
place the various interacting molecules
involved.
• They are either bound to the ER or lie
free in the cytoplasm.
• They
may
form
polysomes
(polyribosomes),
collections
of
ribosomes strung along messenger RNA.
Protein Synthesis
• The code to make a particular protein lies
on a DNA molecule
• in the nucleus, mRNA copies the code
from the DNA (transcription), then leave
towards the cytoplasm to a ribosome to
assemble the protein from the amino
acids
• tRNA will collect all the amino acids
from the cytoplasm to match the amino
acids brought
ENDOPLASMIC RETICULUM
Biosynthetic Factory of the Cell
Structure:
• A
system
of
flattened,
membrane-bounded sacs called cisternae,
forming tubes and sheets.
• It is continuous with the outer membrane
of the nuclear envelope.
Functions:
• If ribosomes are found on its surface it is
called ROUGH ER, and transports
proteins made by the ribosomes through
the cisternae.
• SMOOTH ER, contains no ribosomes, is
a site of lipid and steroid synthesis or
detoxification of a variety of poisons
within the cell.
GOLGI APPARATUS
Shipping and Receiving Center
Structure:
• A stack of flattened, membrane-bounded
sacs, called cisternae, continuously being
formed at one end of the stack and
budded off as vesicles at the other.
• Stacks may form discrete dictyosomes as
in plant cells, or an extensive network as
in many animal cells.
Functions:
• Packaging, sorting and refining of
products that the cells are making.
• Processing in cisternae and transport in
vesicles of many cell materials, such as
enzymes from the ER.
• Often involved in secretion and lysosome
formation.
LYSOSOMES
Digestive compartments of the Cell
Structure:
⮚
A simple spherical sac bounded by a
single
membrane
and containing
digestive (hydrolytic) enzymes.
⮚
Contents appear homogenous.
Functions:
• Many functions, all concerned with
breakdown of structures and molecules.
• Responsible in digestion of nutrients,
bacteria and damaged organelles.
• They are also used to destroy certain cells
in the process known as apoptosis or
programmed cell death during embryonic
development.
MITOCHONDRIA
Power house of the Cell
Structure:
• Surrounded by an envelope of two (2)
membranes, the inner being folded to
form cristae.
• Contains a matrix with a few ribosomes,
a circular DNA molecule and phosphate
granules.
Functions:
• In aerobic respiration cristae are the sites
of oxidative phosphorylation and electron
transport, and the matrix is the site of
Krebs cycle enzymes and fatty acid
oxidation.
CHLOROPLAST
Capture of Light Energy
Structure:
⮚
Large plastid containing chlorophyll and
carrying out photosynthesis.
⮚
It is surrounded by an envelope of two
(2) membranes called thylakoids and
contains a gel-like stroma through which
runs a system of membranes that are
stacked in places to form grana.
⮚
It may store starch.
⮚
The stroma also contains ribosomes, a
circular DNA molecule and lipid
droplets.
Functions:
• It
is the organelle in which
photosynthesis takes place, producing
sugars and other substances from carbon
dioxide and water using light energy
trapped by chlorophyll.
• Light energy is converted to chemical
energy.
VACUOLE
Diverse Maintenance Compartments
Structure:
• A sac bounded by a single membrane
called tonoplast.
• It contains cell sap, a concentrated
solution of various substances, such as
mineral salts, sugars, pigments, organic
acids and enzymes.
• Typically large in mature cells.
Functions:
• Storage of various substances including
waste products.
• It makes an important contribution to the
osmotic properties of the cell.
• Sometimes it functions as a lysosome.
CYTOSKELETON
For support, motility and regulation of the Cell
CELL CYCLE AND DIVISION
Phases of Cell Cycle
A typical eukaryotic cell cycle is illustrated by
human cells in culture.
The cell cycle is divided into two basic phases:
INTERPHASE
• The time during which the cell is
preparing for division by undergoing both
cell growth and DNA replication in an
orderly manner.
•
The interphase lasts more than 95% of
the duration of cell cycle.
• Divided into three phases: Gap 1,
synthesis phase and Gap 2 phase.
M PHASE (MITOSIS PHASE)
• Represents the phase when the actual cell
division or mitosis occurs.
• Starts with the nuclear division,
corresponding to the separation of
daughter chromosomes (karyokinesis)
and usually ends with division of
cytoplasm (cytokinesis).
• Divided into four phases: prophase,
metaphase, anaphase and telophase.
INTERPHASE
GAP 1 (G1) PHASE
• Corresponds to the interval between
mitosis and initiation of DNA replication.
• The cell is metabolically active and
continuously grows but does not replicate
its DNA.
SYNTHESIS (S) PHASE
• Marks the period during which DNA
synthesis or replication takes place.
• The amount of DNA per cell doubles.
• In animal cells, during the S phase, DNA
replication begins in the nucleus, and the
centriole duplicates in the cytoplasm.
GAP 2 (G2) PHASE
• Proteins are synthesized in preparation
for mitosis while cell growth continues.
M PHASE (MITOSIS)
Divided into the following four stages of nuclear
division:
• Prophase
• Metaphase
• Anaphase
• Telophase
PROPHASE
• Marked by the initiation of condensation
of chromosomal material.
• The chromosomal material becomes
untangled during the process of
chromatin condensation.
• The centriole, which had undergone
duplication during S phase of interphase,
now begins to move towards opposite
poles of the cell.
METAPHASE
• Characterized by all the chromosomes
coming to lie at the equator with one
chromatid
of
each
chromosome
connected by its kinetochore to spindle
fibers from one pole and its sister
chromatid connected by its kinetochore to
spindle fibers from the opposite pole.
ANAPHASE
• Centromeres split and chromatids
separate.
• Chromatids move to opposite poles.
• Formation of a cleavage furrow
TELOPHASE
• Chromosomes cluster at opposite spindle
poles and their identity is lost as discrete
elements.
• Nuclear envelope assembles around the
chromosome clusters.
• Nucleolus, Golgi complex and ER
reform.
CYTOKINESIS
❖ Mitosis
accomplishes not only the
segregation of duplicated chromosomes
into daughter nuclei (karyokinesis), but
the cell itself is divided into two daughter
cells by a separate process called
cytokinesis
MEIOSIS
The production of offspring by sexual
reproduction that includes the fusion of two
gametes, each with a complete haploid set of
chromosomes.
MEIOSIS 1
PROPHASE 1
• It is subdivided into the following five
phases based on chromosomal behavior:
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
Abnormal cell growth and division characterize
tumors and cancer.
• When the rates of cell division and
growth exceed the rate of cell death, a
tissue begins to enlarge causing the
formation of tumor or neoplasm. Benign
tumor & Malignant tumor
• Cancer is an illness that results from the
abnormal proliferation of any of the cells
in the body.
Sure, let's break down some key cell structures
and their functions in a simple and understandable
way:
12. Cell Wall (in plant cells):
- Function: It's like the cell's armor. It provides
protection and structural support to plant cells.
1. Cell Membrane (Plasma Membrane):
- Function: It's like a cell's security guard. It
controls what goes in and out of the cell, keeping
the cell's internal environment stable.
These are the basic structures that make up a cell
and perform various functions to keep the cell
alive and functioning. Just like how different parts
of a factory work together to produce products,
these cell structures work together to maintain life
processes within the cell.
2. Nucleus:
-Function: Think of it as the cell's control center
or boss's office. It holds the cell's DNA and tells
the cell what to do.
3. Cytoplasm:
- Function: This is like the cell's workspace. It's
a jelly-like substance where many cell activities
happen.
4. Mitochondria:
- Function: Mitochondria are like tiny power
plants. They produce energy (called ATP) for the
cell.
5. Endoplasmic Reticulum (ER):
- Function: ER is like a factory conveyor belt. It
helps make and transport proteins and lipids in the
cell.
6. Golgi Apparatus:
- Function: Think of it as the cell's packaging
and shipping department. It modifies and packages
proteins and other molecules for transport.
7. Vacuole (in plant cells):
- Function: This is like the cell's storage room. It
stores water, nutrients, and other substances.
8. Lysosome:
- Function: Lysosomes are like the cell's
recycling center. They break down waste materials
and old cell parts.
9. Ribosomes:
- Function: Ribosomes are the cell's builders.
They make proteins.
10. Cytoskeleton:
- Function: Think of it as the cell's scaffolding.
It helps maintain the cell's shape and allows for
movement.
11. Chloroplasts (in plant cells):
- Function: Chloroplasts are like tiny solar
panels. They capture sunlight and convert it into
energy through photosynthesis.
HUMAN ANATOMY / Lesson 3
THE SKELETAL SYSTEM
FUNCTIONS OF THE MUSCULAR SYSTEM
• Support - provides structural support for the
entire body
• Storage Minerals and Lipids – stores calcium and
fats
in the yellow bone marrow
• Blood Cell Production – hematopoiesis
• Protection – surrounds soft tissues and organs
• Movement – serves as point of attachment to
muscles
CLASSIFICATION
1. Long Bone - Femur
2. Short Bone - Cuneiform
3. Flat Bone - Sternum
4. Irregular Bone - Vertebra
5. Sesamoid bone – Patella
BONE MATRIX
• Calcium phosphate makes up almost two-thirds
of the weight of bone. Forms hydroxyapatite
• Collagen fibers
• Different bone cell types
✓ Osteogenic Cells – maintain populations of
osteoblast / produce osteoblasts
✓ Osteoblast – produce bone matrix
(ossification) / immature bone cell that secretes
organic components of matrix
✓ Osteocytes – makes up cell population / mature
bone cell that maintains the bone matrix
✓ Osteoclast – cells that absorbs and removes
bone matrix / multinucleate cell that secretes acids
and enzymes to dissolve bone matrix
SURFACE COVERING OF BONE
PERIOSTEUM
• Superficial layer of compact bones that covers all
bones
ENDOSTEUM
• An incomplete cellular layer, lines the medullary
cavity
COMPACT BONE VS SPONGY BONE
COMPACT BONE
• Outer bone and rigid
• Contains osteon – functional unit
SPONGY BONE
• Inner bone and porous
• Contains trabeculae
Bone Formation Process
OSSIFICATION – the formation of bone by
osteoblast
Types of bone cells
• Osteocytes
• Osteoblast
2 types of ossification
• Intramembranous ossification - flat bones,
clavicle, and most of the cranial bones
• Endochondral ossification – all long bones of
axial and appendicular bones
NUTRITIONAL
AND
HORMONAL
EFFECTS ON BONE
Minerals – Normal bone growth and
maintenance cannot take place without a constant
dietary source of calcium and phosphorus.
• Calcitriol – hormone calcitriol is essential for
normal calcium and phosphate ion absorption in
the digestive tract.
• Vitamin C – stimulates osteoblast differentiation
• Vitamins A, K and B12– Vitamin A is important
for normal bone growth in children. Vitamins
K and B12 are required for the synthesis of
proteins in normal bone.
• Growth Hormone and Thyroxine - Growth
hormone, produced by the pituitary gland, and
thyroxine, from the thyroid gland, stimulate bone
growth.
Bone Remodeling
Bone remodeling is the process by which
osteoclasts eat old bone and stimulate osteoblasts
to make new bone.
HUMAN ANATOMY / Lesson 4
THE MUSCULAR SYSTEM
INTRODUCTION TO MUSCULAR SYSTEM
• The muscular system is responsible for the
movement of the human body.
• Attached to the bones are about 700 named
muscles.
• There are three types of muscle tissue: smooth,
cardiac, and skeletal.
CHARACTERISTICS OF MUSCLE
• Muscle cells are elongated (muscle cell = muscle
fiber)
• Contraction of muscles is due to the movement
of myofilaments – the muscle cell equivalent of
the microfilaments of cytoskeletons
• All muscles share some terminology
✓ Prefix myo refers to muscle
✓ Prefix sarco refers to flesh
• Smooth muscle, found in the walls of the hollow
internal organs
Example: blood vessels, gastrointestinal tract
• Non-striated
• Involuntary
• Cardiac muscle, found in the walls of the heart
• Striated
• Involuntary
• Skeletal muscle, attached to bones, is responsible
for skeletal movements
• Striated
• Voluntary
STRUCTURE OF SKELETAL MUSCLE
• Muscle Fiber – single cylindrical muscle cell
• Epimysium – fibrous tissue envelope that
surrounds skeletal muscle
• Perimysium – collagenous connective tissue that
separates the skeletal muscle tissue into muscle
fascicles
• Fascicle – bundle of muscle fibers
• Endomysium – surrounds individual muscle
fibers
• Myofibril – filaments containing contractile
proteins
• Sarcomere – repeating functional units of the
muscle fiber
• Myofilaments – Bundles of protein filaments in
myofibrils (actin / myosin)
• A Band – Region of overlapping actin and
myosin
• I Band – region of the sarcomere that contains
thin filaments but no thick filaments
SKELETAL MUSCLE ATTACHMENTS
• Epimysium blends into a connective tissue
attachment
• Tendon – cord-like structure
• Aponeuroses – sheet-like structure
• Sites of muscle attachment
• Bones
• Cartilages
• Connective tissue coverings
SLIDING FILAMENT THEORY
The sliding filament theory is a suggested
mechanism of contraction of striated muscles,
actin and myosin filaments to be precise, which
overlap each other resulting in the shortening of
the muscle fiber length.
1. the H bands and I bands of the sarcomeres
narrow,
2. the zones of overlap widen,
3. the Z lines move closer together, and
4. the width of the A band remains constant
1. Myosin heads split ATP and become reoriented
and energized
2. Myosin heads bind to actin, forming
crossbridges
3. Myosin heads rotates toward center of the
sarcomere (power stroke)
4. As myosin heads bind ATP, the crossbridges
detach from actin
MUSCLE Groups
• Size: vastus (huge); maximus (large); longus
(long); minimus (small); brevis (short).
• Shape: deltoid (triangular); rhomboid (like a
rhombus with equal and parallel sides); latissimus
(wide); teres (round); trapezius (like a trapezoid, a
four-sided figure with two sides parallel).
• Direction of fibers: rectus (straight); transverse
(across);
oblique
(diagonally); orbicularis
(circular).
• Location: pectoralis (chest); gluteus (buttock or
rump); brachii (arm); supra- (above); infra(below); sub- (under or beneath); lateralis (lateral).
• Number of origins: biceps (two heads); triceps
(three heads); quadriceps (four heads).
• Action: abductor (to abduct a structure);
adductor (to adduct a structure); flexor (to flex a
structure); extensor (to extend a structure); levator
(to lift or elevate a structure); masseter (a chewer).
GROUP ACTIONS
• Muscles act in groups to produce movements
✓ Agonist – muscle causing desired action
✓ Antagonist – muscle that is relaxed
✓ Synergist – help stabilize movements
✓ Fixator
• Opposing pairs: Dorsiflexion/Plantar flexion,
Inversion/Eversion, Supination/Pronation
✓ Origin – The place on the stationary bone that
is connected via tendons
✓ Insertion – The place on the moving bone that
is connected to the muscle via tendons
THE HEAD AND NECK
• Humans have well-developed muscles in the face
that permit a large variety of facial expressions.
✓ There are four pairs of muscles that are
responsible for chewing movements or
mastication
(temporalis,
masseter,
lateral
pterygoid, medial pterygoid).
THE TRUNK
• The muscles of the trunk include those that move
the vertebral column, the muscles that form the
thoracic and abdominal walls, and those that cover
the pelvic outlet.
✓ The erector spinae group of muscles
✓ The muscles of the thoracic wall
✓ The abdomen
✓ The pelvic
THE UPPER EXTREMITIES
• The muscles of the upper extremity include those
that attach the scapula, humerus, located in the
arm or forearm, wrist, and hand.
THE LOWER EXTREMITIES
✓ The largest muscle mass belongs to the
posterior group, the gluteal muscles
✓ Muscles that move the leg are located in the
thigh region.
✓ The muscles located in the leg that move the
ankle and foot are divided into anterior, posterior,
and lateral compartments.
HUMAN ANATOMY / Lesson 5
THE NERVOUS SYSTEM
The nervous system is the most complex body
system.
● Constantly alive with electricity, the
nervous system is the body’s prime
communication
and
coordination
network.
● It is so vast and complex that, an estimate
is that all the individual nerves from one
body, joined end to end, could reach
around the world two and a half times.
FUNCTIONS OF THE NERVOUS SYSTEM
1. Sensory input – gathering information
● To monitor changes occurring inside and
outside the body (changes = stimuli)
2. Integration –
● to process and interpret sensory input and
decide if action is needed.
3. Motor output
●
A response to integrated stimuli
●
The response activates muscles or glands
STRUCTURAL CLASSIFICATION OF THE
NERVOUS SYSTEM
●
Central nervous system (CNS)
●Brain
●Spinal cord
●
Peripheral nervous system (PNS)
●
Nerve outside the brain and spinal
cord
⮚
Together, the central nervous system
(CNS) and the peripheral nervous systems (PNS)
transmit and process sensory information and
coordinate bodily functions.
FUNCTIONAL CLASSIFICATION OF THE
PERIPHERAL NERVOUS SYSTEM
●
Sensory (afferent) division
●
Nerve
fibers
that
carry
information to the central nervous system
FUNCTIONAL CLASSIFICATION OF THE
PERIPHERAL NERVOUS SYSTEM
●
Motor (efferent) division
●
Two subdivisions
●Somatic nervous system = voluntary
●Autonomic
nervous system =
involuntary
NERVOUS TISSUE: SUPPORT
(NEUROGLIA OR GLIA)
●
Astrocytes
● Abundant, star-shaped cells
● Brace neurons
● Form barrier
between
capillaries
and neurons
● Control
the
chemical
environment of
the brain (CNS)
CELLS
NERVOUS TISSUE: SUPPORT CELLS
● Microglia (CNS)
● Spider-like phagocytes
● Dispose of debris
● Ependymal cells (CNS)
● Line cavities of the
brain and spinal cord
● Circulate
cerebrospinal
fluid
● Oligodendrocytes(CNS)
● Produce myelin sheath around
nerve fibers in the central
nervous system
NEUROGLIA VS. NEURONS
• Neuroglia divide.
• Neurons do not.
• Most brain tumors are “gliomas.”
• Most brain tumors involve the neuroglia
cells, not the neurons.
• Consider the role of cell division in
cancer!
SUPPORT CELLS OF THE PNS
● Satellite cells
● Protect neuron cell bodies
● Schwann cells
● Form myelin sheath in the
peripheral nervous system
●
●
Nervous Tissue: Neurons
● Neurons = nerve cells
● Cells specialized to transmit
messages
● Major regions of neurons
● Cell body – nucleus
and metabolic center of
the cell
● Processes – fibers that
extend from the cell
body (dendrites and
axons)
NEURON ANATOMY
● Cell body
● Nucleus
● Large nucleolus
Synaptic cleft – gap between
adjacent neurons
Synapse – junction between
nerves
NERVE FIBER COVERINGS
● Schwann cells – produce myelin sheaths
in jelly-roll like fashion
● Nodes of Ranvier – gaps in myelin sheath
along the axon
NEURON CELL BODY LOCATION
● Most are found in the central nervous
system
● Gray matter – cell bodies and
unmylenated fibers
● Nuclei – clusters of cell bodies
within the white matter of the
central nervous system
● Ganglia – collections of cell bodies
outside the central nervous system
FUNCTIONAL
CLASSIFICATION
OF
NEURONS
● Sensory (afferent) neurons
● Carry impulses from the sensory
receptors
● Cutaneous sense organs
● Proprioceptors – detect
stretch or tension
● Motor (efferent) neurons
● Carry impulses from the central
nervous system
FUNCTIONAL
CLASSIFICATION
OF
NEURONS
● Interneurons (association neurons)
● Found in neural pathways in the
central nervous system
● Connect sensory and motor
neurons
●
Extensions outside the cell body
● Dendrites – conduct impulses
toward the cell body
● Axons – conduct impulses away
from the cell body
AXONS AND NERVE IMPULSES
● Axons end in axonal terminals
● Axonal terminals contain vesicles with
neurotransmitters
● Axonal terminals are separated from the
next neuron by a gap
STRUCTURAL
CLASSIFICATION
OF
NEURONS
● Multipolar neurons – many extensions
from the cell body
● Bipolar neurons – one axon and one
dendrite
● Unipolar neurons – have a short single
process leaving the cell body
HOW
NEURONS
FUNCTION
(PHYSIOLOGY)
● Irritability – ability to respond to stimuli
● Conductivity – ability to transmit an
impulse.
●
The plasma membrane at rest is
polarized.
● Fewer positive ions are inside
the cell than outside the cell.
STARTING A NERVE IMPULSE
● Depolarization – a stimulus depolarizes
the neuron’s membrane.
● A depolarized membrane allows sodium
(Na+) to flow inside the membrane.
● The exchange of ions initiates an action
potential in the neuron.
THE ACTION POTENTIAL
● If the action potential (nerve impulse)
starts, it is propagated over the entire
axon.
● Potassium ions rush out of the neuron
after sodium ions rush in, which
repolarizes the membrane.
● The sodium-potassium pump restores the
original configuration.
● This action requires ATP.
NERVE IMPULSE PROPAGATION
● The impulse continues to move toward
the cell body.
● Impulses travel faster when fibers have a
myelin sheath.
Continuation of the Nerve Impulse between
Neurons
● Impulses are able to cross the synapse to
another nerve.
● Neurotransmitter is released
from a nerve’s axon terminal.
● The dendrite of the next neuron
has receptors that are stimulated
by the neurotransmitter.
● An action potential is started in
the dendrite.
THE REFLEX ARC
● Reflex – rapid, predictable,
involuntary responses to stimuli
and
●
Reflex arc – direct route from a sensory
neuron, to an interneuron, to an effector
TYPES OF REFLEXES AND REGULATION
● Autonomic reflexes
● Smooth muscle regulation
● Heart and blood pressure
regulation
● Regulation of glands
● Digestive system regulation
● Somatic reflexes
● Activation of skeletal muscles
CENTRAL NERVOUS SYSTEM (CNS)
● CNS develops from the embryonic neural
tube
● The neural tube becomes the
brain and spinal cord
● The opening of the neural tube
becomes the ventricles
● Four chambers within
the brain
● Filled
with
cerebrospinal fluid
REGIONS OF THE BRAIN
● Cerebral hemispheres
● Diencephalon
● Brain stem
● Cerebellum
CEREBRAL HEMISPHERES (CEREBRUM)
● Paired (left and right) superior parts of
the brain
● Include more than half of the brain mass
● The surface is made of ridges (gyri) and
grooves (sulci)
●
Broca’s area – involved in our ability to
speak
Sensory and Motor Areas of the Cerebral Cortex
LOBES OF THE CEREBRUM
● Fissures (deep grooves) divide the
cerebrum into lobes
● Surface lobes of the cerebrum
● Frontal lobe
● Parietal lobe
● Occipital lobe
● Temporal lobe
LOBES OF THE CEREBRUM
SPECIALIZED AREA OF THE CEREBRUM
● Cerebral areas involved in special senses
● Gustatory area (taste)
● Visual area
● Auditory area
● Olfactory area
SPECIALIZED AREA OF THE CEREBRUM
● Interpretation areas of the cerebrum
● Speech/language region
● Language comprehension region
● General interpretation area
Specialized Area of the Cerebrum
SPECIALIZED
AREAS
OF
THE
CEREBRUM
● Somatic sensory area – receives impulses
from the body’s sensory receptors
● Primary motor area – sends impulses to
skeletal muscles
●
The pituitary gland is attached to
the hypothalamus
EPITHALAMUS
● Forms the roof of the third ventricle
● Houses the pineal body (an endocrine
gland)
● Includes the choroid plexus – forms
cerebrospinal fluid
LAYERS OF THE CEREBRUM
● Gray matter
● Outer layer
● Composed mostly of neuron cell
bodies
● White matter
● Fiber tracts inside the gray
matter
● Example:
corpus
callosum
connects hemispheres
● Basal nuclei – internal islands of gray
matter
● Regulates voluntary motor activities by
modifying info sent to the motor cortex
● Problems = ie unable to control muscles,
spastic, jerky
● Involved in Huntington’s and Parkinson’s
Disease
DIENCEPHALON
● Sits on top of the brain stem
● Enclosed by the cerebral hemispheres
● Made of three parts
● Thalamus
● Hypothalamus
● Epithalamus
THALAMUS
● Surrounds the third ventricle
● The relay station for sensory impulses
● Transfers impulses to the correct part of
the cortex for localization and
interpretation
HYPOTHALAMUS
● Under the thalamus
● Important autonomic nervous system
center
● Helps regulate body temperature
● Controls water balance
● Regulates metabolism
● An important part of the limbic
system (emotions)
BRAIN STEM
● Attaches to the spinal cord
● Parts of the brain stem
● Midbrain
● Pons
● Medulla oblongata
MIDBRAIN
● Mostly composed of tracts of nerve fibers
● Reflex centers for vision and
hearing
● Cerebral aquaduct – 3rd-4th
ventricles
PONS
● The bulging center part of the brain stem
● Mostly composed of fiber tracts
● Includes nuclei involved in the control of
breathing
MEDULLA OBLONGATA
● The lowest part of the brain stem
● Merges into the spinal cord
● Includes important fiber tracts
● Contains important control centers
● Heart rate control
● Blood pressure regulation
● Breathing
● Swallowing
● Vomiting
CEREBELLUM
● Two hemispheres with convoluted
surfaces
● Provides involuntary coordination of
body movements
PROTECTION
OF
THE
NERVOUS SYSTEM
● Scalp and skin
● Skull and vertebral column
● Meninges
CENTRAL
●
●
●
●
Cerebrospinal fluid
Blood brain barrier
MENINGES
● Dura mater
● Double-layered
external
covering
● Periosteum – attached
to surface of the skull
● Meningeal layer – outer
covering of the brain
● Folds inward in several areas
● Arachnoid layer
● Middle layer
● Web-like
● Pia mater
● Internal layer
● Clings to the surface of the brain
Nervous
tissue does not
regenerate
Cerebral edema
● Swelling from the inflammatory
response
● May compress and kill brain
tissue
CEREBROVASCULAR ACCIDENT (CVA)
● Commonly called a stroke
● The result of a ruptured blood vessel
supplying a region of the brain
● Brain tissue supplied with oxygen from
that blood source dies
● Loss of some functions or death may
result
SPINAL CORD
● Extends from the medulla oblongata to
the region of T12
● Below T12 is the cauda equina (a
collection of spinal nerves)
● Enlargements occur in the cervical and
lumbar regions
CEREBROSPINAL FLUID
● Similar to blood plasma composition
● Formed by the choroid plexus
● Forms a watery cushion to protect the
brain
● Circulated in arachnoid space, ventricles,
and central canal of the spinal cord
BLOOD BRAIN BARRIER
● Includes the least permeable capillaries of
the body
● Excludes many potentially harmful
substances
● Useless against some substances
● Fats and fat soluble molecules
● Respiratory gases
● Alcohol
● Nicotine
● Anesthesia
TRAUMATIC BRAIN INJURIES
● Concussion
● Slight brain injury
● No permanent brain damage
● Contusion
● Nervous
tissue
destruction
occurs
ALZHEIMER’S DISEASE
● Progressive degenerative brain disease
● Mostly seen in the elderly, but may begin
in middle age
● Structural changes in the brain include
abnormal protein deposits and twisted
fibers within neurons
● Victims experience memory loss,
irritability, confusion and ultimately,
hallucinations and death
SPINAL CORD ANATOMY
● Exterior white mater – conduction tracts
CLASSIFICATION OF NERVES
● Mixed nerves – both sensory and motor
fibers
● Afferent (sensory) nerves – carry
impulses toward the CNS
● Efferent (motor) nerves – carry impulses
away from the CNS
●
●
●
●
Internal gray matter - mostly cell bodies
● Dorsal (posterior) horns
● Anterior (ventral) horns
Central canal filled with cerebrospinal
fluid
Meninges cover the spinal cord
Nerves leave at the level of each
vertebrae
● Dorsal root
● Associated with the
dorsal root ganglia –
collections
of cell
bodies outside the
central nervous system
● Ventral root
PERIPHERAL NERVOUS SYSTEM
● Nerves and ganglia outside the central
nervous system
● Nerve = bundle of neuron fibers
● Neuron fibers are bundled by connective
tissue
STRUCTURE OF A NERVE
● Endoneurium surrounds each fiber
● Groups of fibers are bound into fascicles
by perineurium
● Fascicles are bound together by
epineurium
CRANIAL NERVES
I. The olfactory nerve carries sensory input for
smell
II. The optic nerve carries sensory input for vision
III. The oculomotor nerve controls muscles of the
eye and eyelid
IV. The trochlear nerve (TRŎK lee ur) controls the
eyeball
V. The trigeminal nerve (try JEM ǐ nul) controls
the face, nose, mouth, forehead, top of head, and
jaw.
VI. The abducens nerve (ab DŪ senz) also
controls the eyeball.
VII. The facial nerve controls muscles of the face
and scalp, and part of the tongue for sense of taste.
VIII. The auditory or cochlear nerve provides
sensory
X.The vagus (VĀ gus) nerve is the longest cranial
nerve, extending to and controlling the heart,
lungs, stomach, and intestines.
XI.
The accessory nerve permits movement
of the head and shoulders.
XII.
The hypoglassal nerve
(hī pah
GLOSS ul) controls the muscles of the
tongue.
●
●
Consists of only motor nerves
Divided into two divisions
● Sympathetic division
● Parasympathetic division
COMPARISON
OF
SOMATIC
AUTONOMIC NERVOUS SYSTEMS
AND
Anatomy of the Autonomic Nervous System
SPINAL NERVES
● There is a pair of spinal nerves at the
level of each vertebrae for a total of 31
pairs
● The hypothalamus is one of the last areas
of the brain to develop
● No more neurons are formed after birth,
but growth and maturation continues for
several years (new evidence!)
● The brain reaches maximum weight as a
young adult
● However, we can always grow dendrites!
AUTONOMIC NERVOUS SYSTEM
● The involuntary branch of the nervous
system
AUTONOMIC FUNCTIONING
● Sympathetic – “fight-or-flight”
● Response to unusual stimulus
● Takes over to increase activities
● Remember as the “E” division =
exercise,
excitement,
emergency, and embarrassment
● Parasympathetic
–
housekeeping
activities
● Conserves energy
● Maintains daily necessary body
functions
● Remember as the “D” division digestion,
defecation,
and
diuresis
DEVELOPMENT
ASPECTS
OF THE
NERVOUS SYSTEM
● The nervous system is formed during the
first month of embryonic development
● Any maternal infection can have
extremely harmful effects.
Cell Body (Soma):
Function: Control center of the neuron.
Dendrites:
Function: Receive incoming signals.
Axon:
Function: Transmit outgoing signals.
Neurofibrils:
Function: Thread-like structures providing cell
support.
Schwann Cells:
Function: Create myelin in PNS, support nerve
regeneration.
Collateral Branch:
Function: Side branches on axon for
communication.
Mitochondrion (Mitochondria):
Function: Produces cell energy (ATP).
Nissl Substance (Nissl Bodies):
Function: Clusters in cell body, involved in protein
synthesis.
_
Serotonin:
Function: Makes you feel happy and relaxed. It
helps regulate mood, sleep, and appetite. Think of
it as your mood stabilizer.
Dopamine:
Function: Makes you feel rewarded and
motivated. It's responsible for pleasure and
reinforcement. Think of it as your "feel good"
messenger.
Cell Membrane:
Function: Outer cell covering that regulates
substance passage.
Acetylcholine:
Function: Helps with muscle control and memory.
Think of it as the "muscle and memory"
transmitter.
Myelin Sheath:
Function: Fatty insulation around axons, speeds up
nerve signals.
GABA (Gamma-Aminobutyric Acid):
Function: Calms your brain down. It's like a
natural stress-reliever, promoting relaxation.
Nucleus:
Function: Central cell part containing genetic
information.
Glutamate:
Function: Speeds things up in your brain. It's
important for learning and memory, but too much
can be harmful.
Axon Terminal:
Function: End of axon, sends chemical signals.
Axon Hillock:
Function: Link between cell body and axon,
initiates nerve impulses.
Node of Ranvier:
Function: Gaps in myelin sheath, speeds nerve
signal transmission.
Norepinephrine (Noradrenaline):
Function: Helps you stay alert and focused. It's
like your brain's way of saying, "Wake up!"
Endorphins:
Function: Act as natural painkillers and mood
lifters. They're released during exercise,
excitement, and even laughter.
Oxytocin:
Function: Known as the "love hormone." It's
involved in social bonding, trust, and maternal
instincts.
Histamine:
Function: Regulates wakefulness and allergic
reactions. Too much can make you feel itchy or
sleepy.
Epinephrine (Adrenaline):
Function: Prepares your body for the "fight or
flight" response in stressful situations. It increases
heart rate and alertness.
These neurotransmitters act like messengers in
your brain, helping nerve cells communicate with
each other. They play vital roles in your mood,
memory, movement, and overall brain and body
function.