The nervous system has three main functions - sensory, integrative, and motor. It is composed of the central nervous system (brain and spinal cord) and peripheral nervous system. The CNS integrates sensory input and directs motor responses. Neurons communicate via electrical or chemical synapses to transmit signals. Muscles contract when calcium is released following an action potential, causing the binding of actin and myosin. There are three main types of muscle - skeletal, smooth, and cardiac. Blood functions include transport, defense, and hemostasis. It contains plasma, red blood cells, white blood cells, and platelets.

1. NERVOUS SYSTEM

2. Functions
1. Sensory Functions: detecting internal and external stimuli.
2. Integrative Functions: CNS integrates sensory input and
makes decisions regarding appropriate responses
3. Motor Functions: Response to integration decisions.

4. Components of the Nervous System
• Central Nervous System
– Brain
– Spinal Cord
• Peripheral Nervous System
– Sensory and Motor Nerves
– Cranial Nerves
– Spinal Nerves
• Autonomic
– Sympathetic
– Parasympathetic

5. Organization of Nervous System

6. Central Nervous System

7. Autonomic Nervous System

8. Central Nervous System
– Brain and spinal cord
– Necessary for the maintenance of homeostasis
– Contains 1011 neurons
– Contains 1014 synapses
– Responsible for everything we perceive, do, feel,
and think

9. Structure of a Neuron
Dendrites: Receives stimuli from synapses or sensory
receptors.
Cell Body: Contains nucleus and nissl bodies, a form of
rough endoplasmic reticulum.
Axon: Carries nerve impulses away from the cell bodies
and interacts with muscle, glands, or other neurons.

11. One way to classify neurons is by the number of extensions that extend
from the neuron's cell body (soma).
• Bipolar neurons have two
processes extending from the
cell body (examples: retinal
cells, olfactory epithelium
cells).
• Pseudounipolar cells
(example: dorsal root ganglion
cells). Actually, these cells
have 2 axons rather than an
axon and dendrite. One axon
extends centrally toward the
spinal cord, the other axon
extends toward the skin or
muscle.
• Multipolar neurons have
many processes that extend
from the cell body. However,
each neuron has only one
axon (examples: spinal motor
neurons, pyramidal neurons,
Purkinje cells).

13. Glial Cells
– 90% of CNS is composed of glia
– Five types of glial cells
• Astrocyte—numerous functions
• Ependymal cells—lines cavities
• Microglia—phagocytes
• Oligodendrocytes—form myelin
• Schwann cells (located in PNS)—form myelin

15. Astrocytes
– Development of neural connections
– Possibly modulates synaptic activity
– Removes neurotransmitter from synaptic cleft
– Communicates to neurons through chemical
messengers
– Protects neurons against toxic substances
and oxidative stress

16. Microglia
– Protect CNS from foreign matter through
phagocytosis
• Bacteria
• Dead or injured cells
– Protect CNS from oxidative stress

17. Ependymal Cells: Form blood-brain barrier in
the brain ventricles and central canal of spinal
cord. Produces cerebrospinal fluid and assist in
its circulation.

18. Resting potential
• Using active transport, the neuron moves Na+
ions to the outside of the cell and K+ ions to the
inside of the cell.
• Large molecules in the cell maintain a negative
charge.

19. Action potential
• On receiving a stimulus, sodium gates and
potassium channels open briefly, allowing these
ions to diffuse.
• The gates close, and active transport restores
the resting potential.

21. Mechanism that creates an Action Potential

22. Synapse
• A gap called a synapse controls the
transmission of signals.
• Neurotransmitters cross the synapse and
stimulate the next neuron.

23. Communication between neurons
at a synaptic junction
1. Electrical Synapses: Communication via gap junctions
between smooth muscle, cardiac muscle, and
some neurons of the CNS. Provide fast,
synchronized, and two-way transmission of
information.
2. Chemical Synapses: Communication via chemical
neurotransmitters that diffuse across a synaptic
cleft. Provides slow one-way information flow

26. Communication between neurons
at a synaptic junction
1. Action potential arrives at
a synaptic end bulb.
2. Depolarization of membrane
causes the opening of Ca2+
channels.
3. Increase in (Ca2+) inside of
presynaptic neuron triggers
exocytosis of neurotransmitter
4. Neurotransmitter diffuses across
synaptic cleft and binds to
receptor (ligand-gated channel)
on postsynaptic neuron

27. Communication between neurons
at a synaptic junction
5. Na+ channels open causing a depolarization (Na+
channels) EPSP (excitatory postsynaptic potential)
or a hyperpolarization (Cl-channels) IPSP (inhibitory
post-synaptic potential) of the postsynaptic neuron.
6. If depolarization reaches a threshold, an action
potential is generated on the postsynaptic
neuron.

28. Nerve fiber
• A nerve fiber is a threadlike extension of a
nerve cell and consists of an axon and myelin
sheath (if present) in the nervous system.
There are nerve fibers in the central nervous
system and peripheral nervous system.

30. Communication between neurons at a synaptic
junction
Neurotransmitters
1. Acetylcholine: Found in the PNS and CNS. EPSP and in parasympathetic neurons IPSP.
2. Amino Acids: Glutamate and Aspartate produce EPSP’s in the CNS. Gamma
Aminobutyric Acid (GABA) produces IPSP’s in the CNS. Valium enhances the action of
GABA.
3. Biogenic Amines: Norepinephrine and epinephrine produce EPSP’s in the sympathetic
system. Serotonin controls mood and induction of sleep.
4. Gases: Nitric Oxide produce by the enzyme nitric oxide synthase. Causes vasodilation
and erection.

31. PHYSIOLOGY OF MUSCLE

32. Types
• Skeletal
• Cardiac
• Smooth

33. Muscle Tissue Characteristics
All muscle tissues share basic characteristics
1.Excitability
2.Contractility
3.Elasticity
4.Extensibility

34. Muscle Comparison Chart
Skeletal
Cardiac
Smooth
Cylindrical
Cylindrical &
branched
Fusiform
Yes
Yes
No
Multi-
nucleate &
peripheral
Uninucleate
& central
Uninucleate
& central
Voluntary
Involuntary
Involuntary
None
Intercalated
discs
May be
single-unit or
multi-unit
Muscle
Tissue Cell Shape Striae Nucleus Control
Special
structures

35. Skeletal Muscle
• Located throughout the body connected to bones
and joints
• Striated in appearance
• Under voluntary nervous control
• Maintains body structure

36. Skeletal Muscle Structure

39. Myosin
• Consists of tail, hinge and
heads
– Heads contain active sites for
• Actin
• ATP
• M-line consists of
myomesin and skelemin
proteins
– stabilize the myosin
filaments
– theorized to aid in
transmission of force from
sarcomere to cytoskeletal
intermediate filaments

40. • Thin filaments are composed of
– g-actin molecules in
a helical arrangement
• Contain myosin binding
sites
– nebulin
• Filament that forms
internal support and
attachment for actin
– tropomyosin filaments
– troponin (complex of three molecules)
attached to tropomyosin
• Has binding sites for Ca2+
Thin Filaments

41. Physiology of Contraction
1st – synaptic transmission at the
neuromuscular junction
2nd – excitation-contraction coupling
3rd – contraction-relaxation cycle

42. Figure 11.13
Muscle contraction: Cell events

43. Neuromuscular Junction

44. Neuromuscular Junction
• Region where the motor neuron stimulates the muscle
fiber
• The neuromuscular junction is formed by :
1. End of motor neuron axon (axon terminal)
• Terminals have small membranous sacs (synaptic vesicles)
that contain the neurotransmitter acetylcholine (ACh)
2. The motor end plate of a muscle
• A specific part of the sarcolemma that contains ACh receptors
• Axonal ends and muscle fibers are always separated by a
space called the synaptic cleft

45. Acetylcholine Opens Na+ Channel

48. Muscle Contraction Summary
• Nerve impulse reaches myoneural junction
• Acetylcholine is released from motor neuron
• ACh binds with receptors in the muscle
membrane to allow sodium to enter
• Sodium influx will generate an action potential
in the sarcolemma

49. Muscle Contraction
• Action potential travels down T-tubule
• Sarcoplamic reticulum releases calcium
• Calcium binds with troponin to move the
troponin, tropomyosin complex
• Binding sites in the actin filament are
exposed

50. Muscle Contraction
• Myosin head attach to binding sites and create
a power stroke
• ATP detaches myosin heads and energizes
them for another contaction
• When action potentials cease the muscle stop
contracting

51. Sarcomere Relaxed

52. Sarcomere Partially Contracted

53. Sarcomere Completely Contracted

54. • shortening
• isometric
• lengthening
(Isotonic: shortening against fixed
load, speed dependent on M·ATPase
activity and load)
Three Potential Actions During Muscle Contraction:
Most likely to cause
muscle injury
Biceps muscle shortens
during contraction
Biceps muscle lengthens
during contraction

55. Smooth Muscle
• Smooth muscle fibers contract in a similar manner to
skeletal muscles with a few important functional
similarities and differences.
– Similarities
• Both contractile mechanisms depend on the action of actin and
myosin
• Both are triggered by membrane impulses and the release of
calcium ions
• Both require ATP

56. Smooth Muscle
– Differences:
• Actin has no troponin but has a calcium binding
protein called calmodulin. This protein activities the
actin and myosin crossbridge formation.
• Most of the calcium required for contraction comes
into the cell by diffusion from the extracellular fluid.
• Smooth muscle is more resistant to fatigue and
produces a slower, longer lasting contraction
• It is more energy efficient.

57. Smooth Muscle
– Unconscious control of smooth muscle
contraction
– Nuerotransmitters
• Acetylcholine
• Norepinephrine.
• Excitatory (cause muscle contraction), or
inhibitory (prevent muscle contraction)
depending on the receptor on the smooth
muscle cell membrane.

58. Types of Smooth Muscle

59. Cardiac Muscle
Found only in the heart
• Composed of interconnecting, branching
fibers that are striated
• Each cell has a single nucleus
• Abundant mitochondria
–Depends on aerobic metabolism
• No motor units

60. Cardiac Muscle
• Extensive system of T-tubules
• Well developed sarcoplasmic reticulum
• Contains intercalated disks
• Gap Juntions
• Self-exciting
• Autorhythmic

61. PHYSIOLOGY OF BLOOD

62. Functions of blood
1. Place of exchange of substances between
interstitial fluid and external environment
2. Transport
3. Buffer function
4. To keep body temperature relatively constant
5. Hemostasis
6. Defense function

63. Physical and chemical properties
of blood
Specific gravity
blood: 1.050～1.060. RBC number
plasma: 1.025～1.030. Content of
plasma proteins
RBC:1.090 ～1.092. hemoglobin

64. Components of Blood
Blood is a mixture of cellular components
suspended in plasma:
1. Erythrocytes (RBCs)
2. Leukocytes (WBCs)
Total Blood Volume: 8 % of body weight
2.75 / 5.5 liters of blood is plasma
3. Thrombocytes (platelets)

66. Composition of Blood

67. Hematopoiesis

68. Plasma Proteins
Plasma Proteins: (albumins, globulins, fibrinogen)
1. Maintaining colloid osmotic balance (albumins)
2. Buffering pH changes
3. Transport of materials through blood (such as water
insoluble hormones)
4. Antibodies (e.g. gamma globulins, immunoglobulins)
5. Clotting factors (e.g. fibrinogen)

69. Erythrocyte
– Known as red blood cells (RBC)
• Tiny biconcave-shaped disks
• Thinner in center than around edges
• No nucleus in mature red blood cell
– Average life span = approximately 120
days
– Main component = hemoglobin
– Primary function = transport oxygen to
cells of body

70. Erythropoiesis
– RBC production
– controlled by hormones, especially erythropoietin (EPO) from
the kidney
– three phases of RBC maturation
• production of ribosomes
• synthesis of hemoglobin
• ejection of the nucleus and reduction in organelles
– leave bone marrow as reticulocytes  mature in the blood
stream to become erythrocytes

71. Mechanism of Transport
* 4 Heme Molecules =
* 4 Oxygen Molecules
*Oxygenated Hemoglobin
Bright Red (systemic)
*Deoxygenated Hemoglobin
Blue (venous circulation)
HEMOGLOBIN

72. Thrombocytes - Platelets
 Development
– Megakaryocytes shed small cytoplasmic fragments
– Each fragment surrounded by plasma membrane
 Anatomy
– 250,000-400,000/mm3
– No nucleus, disc shaped
– 2-4 µm diameter with many granules

73. Thrombocytes - Platelets (cont.)
Physiology
• Short life span (5-9
days)
• Help plug small holes in
blood vessels
• Granules contain
regulatory factors
which serve several
important functions in:
• coagulation
• inflammation
• immune defenses

74. Thrombocytes - Platelets (Granules)
• alpha granules
–clotting factors
–platelet derived growth factor (PDGF)
• dense granules
–Ca++, ADP, ATP
–Thromboxane A2,
–vasoconstrictors
–clot promoting enzymes

75. Types of WBC’s
1.Neutrophils
2.Eosinophils
3.Basophils
4.Lymphocytes

76. Neutrophils
* 50-70% of all leukocytes
(most abundant of WBC’s)
* Phagocytes that engulf
bacteria and Debris
* Important in inflammatory
responses

77. Eosinophils
* 1-4% of the WBC's
* Attack parasitic worms
* Important in allergic reactions

78. Basophils
* Release histamine
and heparin
* 0.5% of the WBC's
* Important in Allergic
Reactions
Heparin helps clear fat from blood

79. Monocytes
* Exit blood (diapedesis)
to become macrophages
* 2-6 % of the WBC's
* Phagocytic = defend against
viruses and bacteria

80. Lymphocytes - Physiology
Immune response through lymphocytes responding
to antigen
An antigen is:
– any chemical substance recognized as foreign when
introduced into the body
– substance (usually proteins) that stimulate immune
responses

81. Lymphocytes types
– B-cells
• particularly active in attacking bacteria
• develop into plasma cells to produce antibodies
– bind to antigen to form antibody-antigen (Ag-Ab) complexes
– memory B cells
– T-cells
• attack viruses, fungi, transplants, cancer, some bacteria
• 4 types of cells
– cytotoxic (killer) T cells
– helper T cells
– suppressor T cells
– memory T cells

82. Leukocyte Life Span and Number
5,000 - 10,000 WBC’s/mm3 blood
– RBC/WBC ratio 700/1
Differential WBC count
– Neutrophils 60-70%
– Lymphocytes 20-25%
– Monocytes 3-8%
– Eosinophils 2-4%
– Basophils 0.5-1%

83. Hemostasis
3 mechanisms exist to stop bleeding
First - Vascular Spasm
– Blood vessel constricts when damaged
• vessel wall smooth muscle contracts immediately
• blood flow slows through vessel

84. Hemostasis
 Second - Platelet Plug Formation
1) Platelet adhesion
 platelets stick to exposed collagen
 tissue factors activate platelets
2) Platelet release reaction
 platelets attach to other platelets
 release granule contents (thromboxane A2)
 promote vasoconstriction, platelet activation
and aggregation
3) Platelet aggregation -> platelet plug
 blocks blood loss in small vessels
 less effective in larger vessels

85. Hemostasis
Third - Coagulation
– Gel formation (clotting) in blood plasma traps the
formed elements
– Thrombosis - clotting in a normal vessel
– Hemorrhage - slowed clotting may lead to bleeding

86. Blood Types
• RBC surface has genetically determined antigens, agglutinogens

87. Rhesus factor
–Those expressing Rh antigens are Rh+
–Those without Rh agglutinogens are Rh-
• normally, blood does not contain Rh
agglutinins
• immune system only makes agglutinins in
response to specific exposure to Rh
antigens

89. Thank You