This document provides a summary of the course Anatomy and Physiology. It covers two units - Cell Biology (Unit I) and Physiology of Muscle Contraction (Unit II). Unit I discusses the structure and function of cells, genetics, tissues, organs and body systems. It also covers cellular processes like movement, respiration, responses, nutrition and aging. Unit II describes the structure of skeletal, cardiac and smooth muscles. It explains the mechanisms of contraction in these three muscle types, including excitation-contraction coupling. The document concludes with a discussion of oxygen debt during exercise.

1. COURSE CODE: GNS 110
COURSE TITLE: ANATOMY AND
PHYSIOLOGY
PLACEMENT: FIRST YEAR FIRST
SEMESTER
MJ ADENIYI MSC

2. CELL BIOLOGY (UNIT I)
Introduction
Cell theory
Structure and function of cells
Genetics
Cells, the building block of tissues (types), organs
(types) and systems
Intercellular communication (tight, gap
junction and synapse)

3. Properties of cells
Movements within and across the cell
membrane
Growth of cells
Cellular respiration
Cellular responses and sensitivity
Nutrition
Aging and death
Cell and its environment
Body fluid

4. Homeostasis
Tissue adaptation (hypertrophy and
hyperplasia)
PHYSIOLOGY OF MUSCLE CONTRACTION
(UNIT II)
Introduction
Contractile apparatus
Mechanism of skeletal, cardiac and smooth
muscle contraction
oxygen debt

6. NUCLEUS AND THE GENE
A gene is a basic unit of inheritance capable of transmitting
characteristics from one generation to another.
Genetic information is stored in form of code, carried via mRNA
(transcription) out of the nucleus, decoded by tRNA and protein
synthesis is earned by rRNA (translation)
Genetic disorders include mutation, sex linked disorders,
nondisjunction of autosome (down syndrome), nondisjunction of sex
chromosomes, mosaicism etc.

7. ORGANIZATION OF LIFE
Cells of related structures and functions- Tissue
Types of tissues are epithelial, connective, nervous and muscle
Tissues of related structures and functions Organs
At least there are 22 internal organs in the body
Organs of related structures and functions systems
Systems in the body include cardiovascular, nervous, endocrine,
musculoskeletal, respiratory, reproductive, renal, immune,
integumentary and digestive

10. Cell are connected to one through:
 Tight junction (eg blood brain barrier, blood csf barrier , blood
testis barrier).
 Gap junction (eg cardiac muscles cells, monounit smooth
muscles).
 Synapses are junctions between a neuron and another neuron or a
muscle cell

13. PROPERTIES OF CELLS
MOVEMENT: cells can change their position through amoeboid
movement (eg white blood cells and fibroblast) and ciliary action
(ovum). Cells are capable to move due to their cytoskeleton most
especially the microfilaments (actin, myosin).
CELLULAR RESPIRATION takes place within the cell and results
in production of energy stored in form of ATP. Aerobic respiration
increases ATP production by more than 8 fold the energy release
during anaerobic process

16. NUTRITION: All living cells require nutritive substances to grow.
RESPONSES TO STIMULI: cells do have receptors which sense any
change in their environment
GROWTH AND REPRODUCTION: Eukaryotes increase in
number and size through mitosis. Meiosis occurs during reproduction.
CELLULAR EXCRETION: Metabolic waste products leave the cells
by passive diffusion, active transport, exocytosis.

17. AGING AND DEATH: The exact cause of aging is unknown but
may be due to increase production of free radicals and advanced
glycation end product.
Programmed cell death (beneficial death) is called apoptosis while
necrosis is the death of cells in a tissue or organ caused by injury or
disease.
Clinical death and biological death.

18. CELL AND ITS ENVIRONMENT
Body fluid is about 60% of adult male body weight and 55% of adult
female body weight.
Body cells are bathed by fluid, the internal milieu (internal
environment).
It is 40liters and made up of intracellular fluid ICF (22L) and
extracellular fluid ECF(18L).
ECF consists of vascular fluid (the plasma (2.75L)) and interstitial
fluid and lymph (12L).
Body fluid is reduced in dehydration, diarrhoea, burns etc

19. Body fluid as a medium for exchange of materials
The processes through which substances can be exchanged between
cells and the internal environment are:
 Passive Transport: Down hill movt of substances from area of
higher conc. to area of lower conc. requiring no energy. Eg are
diffusion, carrier mediated or facilitated diffusion. Affected by
temperature, surface area, con gradient,etc.

20.  Active transport: Uphill movt. Requires energy in form of ATP. It
is against the conc. Gradient, electrical or electrochemical gradient. Eg
are primary active transport (Na+-K+ATPase) and secondary active
transport.
 Endocytosis (phagocytosis, pinocytosis), exocytosis and bulk flow
The fluid serves as a medium through which cellular
metabolism takes place.

21. TONICITY
The ratio of effective osmole to plasma is called tonicity
Hypertonic has greater effective osmole than plasma and tend to
result in crenation of cells.
Hypotonic fluid results in swelling (eg hemolysis)
Isotonic is same as plasma.
Inorganic substances or electrolytes are expressed in milliequivalent/l
, organic substances are expressed in mg/dl etc
Osmolality is the amount of osmole per kg weight of solution.
Osmolarity is no of osmole per liter of a solution

22. CONCEPT OF HOMEOSTASIS
 Steady state of internal environment despite external challenges.
 Consists of receptor (input), control centre and effector
 Negative feedback and feed forward feedback helps in achieving
stability
 Positive feedback is also known as vicious cycle

23.  Acid/base equilibrium as a form of homeostasis
 pH of the ECF is 7.35-7.45. Decrease below 7.35 results in
acidosis and increase above 7.45 results in alkalosis.
 pH of ICF is 7.0. Decrease below 7 results in acidosis and increase
above 7 results in alkalosis.
 pH is kept steady by the buffer system, respiratory and renal
mechanisms.
 metabolic acidosis occurs diarrhea, diabetes, etc. metabolic
alkalosis occurs in vomiting and hyperaldosteroidism

24.  Respiratory acidosis occurs during hypoventilation (high partial
pressure of Carbondioxide). COPD can result in respiratory acidosis.
 Respiratory alkalosis occurs during hyperventilation. Emotions,
etc, pregnancy and drug abuse can result in respiratory alkalosis
 High plasma hydrogen and OH ions are called acidemia and
alkalemia respectively

25. CELLULAR ADAPTATION
Hypertrophy: Increase in size as a result of addition or recruitments
of subcellular structures. Eg exercise induced cardiac hyper trophy
(eccentric hypertrophy) and Left ventricular hypertrophy in congestive
heart failure (concentric hypertrophy)
Hyperplasia : Increase in size of a tissue as a result of cell multiplicity
Atrophy: Decrease in size of an organ

26. UNIT II: MUSCLES
INTRODUCTION
 Muscles are specialized tissues or organ located beneath the
skin.
 They are excitable tissues. Excitation can be chemical,
electrical and mechanical with the production of an action
potential.
CLASSIFICATION OF MUSCLES
Muscles can be classified based on four criteria: presence of striation,
control, function and location.

27.  In striated muscles, thin and thick filaments are arranged in regular
pattern. Examples are cardiac and skeletal muscles.
 Skeletal muscle can be consciously stimulated (voluntary muscle)
and is under the control of somatic nervous system. Smooth and
cardiac muscles are involuntary and are under autonomic nervous
system.
 Based on function, muscles can be divided into
-Antagonist: some muscles work opposite to each other

28. to achieve a specific movement eg the role of tricep and bicep brachii
during push down and push up
-Agonist are muscles that work in unison to achieve a specific movement: Eg
inspiration involves the contraction of inspiratory muscles-the external
intercoastal muscle and diaphragm.
-Adductors move part of the body toward the median plane. Contraction of
adductor muscles of larynx (lateral cricoarytenoid, interarytenoid and
cricothyroid) pull the vocal cords together in order to produce a vocal sound

29. -Abductors are muscles that move the body part away from the
median plane. Contraction of abductor muscles of the larynx pulls
the vocal cords apart resulting in the opening of glottis during
inspiration
-Suppinators cause outward and upward rotation of the body or
body part.
-Pronators cause an inward rotation of body or body parts.
 Based on location, cardiac muscle is form the musculature of the
heart, smooth muscles are present in body viscera and skeletal
muscle are in association with bone

30. STRUCTURE OF MUSCLES
Muscles consist of muscle cells called muscle fibers or myocytes. The
composition of cellular components in muscle and the density of the
components vary. However, the following are common:
Sarcolemma (muscle cell membrane), nucleus, mitochondria, golgi
bodies, myofibril( microfilaments as in actin, myosin and
(tropomyosin and troponin are present in skeletal and cardiac muscle
only)), sarcoplasmic reticulum (calcium store house in skeletal and
cardiac muscle) and (calmouduline in smooth muscle), lysosome,
ribosome and rough endoplasmic reticulum.

31. PROPERTIES OF MUSCLE
 Defatigability: While skeletal muscle is defatigable, smooth muscle
are indefatigable.
 Tetanus: Skeletal muscle can be tetanized because of its short
refractory period.Smooth and cardiac muscles are not.
 Muscle tone: Maintenance of a partial state of contraction.
 Excitability: The response of muscle to stimulus through the
production of action potential.
-stimulus is a change in cell environment which triggers response.

32. -stimulus can be weak (subthreshold), of sufficient strength
(threshold) and above threshold (suprathreshold)..
-An excitable tissue responds to stimulus of sufficient strength
(threshold) or suprathreshold or does not respond to weak stimulus
at all. This is All-or-none principle.
-The higher the strength of a stimulus, the shorter the duration for
response (action potential). Strength of stimulus α 1/time taken to
produce action potential.

33. -Action potential is a series of changes that occur in membrane
potential. It consists of resting membrane potential, depolarization
and repolarization.
-Resting membrane potential is the potential difference between the
exterior and interior parts of muscle cells at rest. It is -90mv in skeletal
muscle and cardiac muscle and -49 to-70mv in smooth muscle. It is
due to Na+-K+ atpase and leak potassium channels.

34. -Depolarization: This is an increase in membrane potential. It is due to
influx of sodium ions into the cells. In cardiac and smooth muscle cells
depolarization is prolonged due to activation of slow opening calcium
channels and influx of calcium ions producing what is known as a
plateau.
-Repolarization: Decrease in membrane potential towards the resting
level. It is due to activation of slow opening potassium channel and
efflux of potassium ions (+ve ions). The membrane potential may fall
below the resting level. This is known as after hyperpolarization.

35. ACTION POTENTIAL IN CARDIAC MUSCLE

36. SKELETAL MUSCLES
Figure 1 showing the morphology of skeletal muscle

37. Skeletal muscles weigh about
31kg and constitute around
45% of adult male body mass.

39. Morphology of skeletal muscle

40. TYPES OF SKELETAL MUSCLES

41. Morphology of skeletal muscle

43. NEUROMUSCULAR JUNCTION AND EXCITATION
CONTRACTION COUPLING
 The junction between muscle and nerve is called neuromuscular
junction. It is well developed in skeletal muscle and poor in cardiac and
smooth muscles.
 The nerve cell ends as uncapsulated ending loosing its myelin sheath
and forming motor endplate (presynaptic cell).
 The motor end plate contacts the muscle fiber(postsynaptic cell )
through synaptic cleft. Cholinergic receptor are located on post synaptic
membrane

44. Neuromuscular junction of skeletal muscle

45. Neuromuscular junction in smooth muscle. That of
cardiac muscle looks like this

47. Step by step mechanism of muscle contraction

48. SKELETAL MUSCLE CONTRACTION

49. Excitation contraction coupling in smooth muscles
 Spread of excitation to smooth muscles
 Binding of receptors to muscarinic receptors
 Development of endplate potential
 Influx of calcium ion into the smooth muscle cells and binding of calcium
with calmouduline. Calcium calmouduline activates light chain kinase .
 Activation of myosin head (in smooth muscle) by myosin light chain kinase
 Prolonged sliding of actin over myosin (latch bridge mechanism) in smooth
muscle.

50.  Some drugs enhance the activity of acetylcholine by inhibiting
cholinesterase. Such drugs are called depolarizing blockers eg
are neostigmine, physiostigmine.
 Drug that bind nicotinic cholinergic receptors prevent
transmission of signal are known as non depolarizing blockers
eg are curare (block nicotinic receptor) and atropine (muscarinic
receptor) .

51. Myasthenia gravis is an autoimmune reaction against
nicotinic cholinergic receptor
Tetanus is an apparent sustained contraction due to
repeated stimuli of high frequency
Fatigue is a decrease in muscular activities due to
shortage of neurotransmitter, energy, and increase in
lactic acid

52. OXYGEN DEBT
 Aerobic resynthesis of energy stores does not keep pace with
utilization.
 Characterized by depletion of glucose, oxygen store (hemoglobin
and myoglobin) and energy store (ATP phosphagen system i.e
phosphorylcreatine)
 Accumulation of lactic acid in tissue decreases pH.
 Extra oxygen consumption post-exercise is divided into lactic acid
(to remove lactic acid) and alactacid oxygen debt (to restore
phosphagen system, myoglobin, etc)

53. THANKS