CNS_PNS الجهاز المركزي والجهاز الطرفي

1. Essentials of Anatomy and Physiology
Fifth edition
Seeley, Stephens and Tate
Slide 2.1
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Chapter 8: Nervous System

2. Cerebellum
Slide 7.43a
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 Two hemispheres with convoluted
surfaces
 Provides involuntary coordination of
body movements

3. Cerebellum
Slide 7.43b
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Figure 7.15a

4. Protection of the Central Nervous
System
Slide 7.44a
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 Scalp and skin
 Skull and vertebral column
Figure 7.16a

5. Protection of the Central Nervous
System
Slide 7.44a
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 Meninges:
Dura mater
Arachnoid
Pia Mater
Figure 7.16a

6. Protection of the Central Nervous
System
Slide 7.44b
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 Cerebrospinal fluid: subarachnoid space
 Blood brain barrier
Figure 7.16a

7. Meninges
Slide 7.45a
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 Dura mater
Double-layered external covering
Periosteum – attached to surface of the
skull
Meningeal layer – outer covering of the
brain
Folds inward to support hemispheres

8. Meninges
Slide 7.45b
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 Arachnoid layer
Middle layer
Web-like
 Pia mater
Internal layer
Clings to the surface of the brain

9. Cerebrospinal Fluid
Slide 7.46
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 Similar to blood plasma
 Formed by the choroid plexus
 Forms a watery cushion to protect the
brain
 Circulated in subarachnoid space,
ventricles, and central canal of the
spinal cord

10. Ventricles and Location of the
Cerebrospinal Fluid
Slide 7.47a
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Figure 7.17a

11. Ventricles and Location of the
Cerebrospinal Fluid
Slide 7.47b
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Figure 7.17b

12. Blood Brain Barrier
Slide 7.48
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 The least permeable capillaries of the
body + astrocyte processes
 Excludes many potentially harmful
substances
 Useless against some substances
Fat soluble substances
Anesthetics

13. Blood Brain Barrier
Slide 7.48
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 “Good news”: keeps out most harmful
substances
Alcohol, viruses, some drugs
 “Bad news”: keeps out most helpful
substances
Antibiotics, chemotherapy drugs

14. Traumatic Brain Injuries
Slide 7.49
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 Concussion
Slight brain injury
Usually no permanent damage
 Contusion
Nervous tissue destruction occurs
Nervous tissue does not regenerate
 Cerebral edema
May compress and kill brain tissue

15. Cerebrovascular Accident (CVA)
Slide 7.50
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 Commonly called a stroke
 The result of a ruptured blood vessel
 Brain tissue supplied with oxygen from
that blood source dies
 Loss of some functions or death may
result

16. Alzheimer’s Disease
Slide 7.51
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 Progressive degenerative brain disease
 Mostly seen in the elderly, but may
begin in middle age
 Structural changes in the brain due to
abnormal proteins
 Symptoms: memory loss, irritability,
confusion, ultimately hallucinations and
death

17. Spinal Cord
Slide 7.52
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 Extends from the
medulla oblongata to
L-1
 Below is the cauda
equina
 Enlargements in the
cervical and lumbar
regions
Figure 7.18

18. Spinal Cord Anatomy
Slide 7.53a
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 White mater – conduction tracts
 Superficially located
Figure 7.19

19. Spinal Cord Anatomy
Slide 7.53b
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 Gray matter - mostly cell bodies, deep
 Dorsal (posterior) gray horns
 Ventral (anterior) gray horns
Figure 7.19

20. Spinal Cord Anatomy
Slide 7.53c
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 Central canal: holds cerebrospinal fluid
Figure 7.19

21. Spinal Cord Anatomy
Slide 7.54
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 Meninges: same as brain
 Spinal Nerves attached to each spinal
segment
Dorsal root: sensory
 Associated with the dorsal root ganglia
Ventral root: motor

22. Peripheral Nervous System
Slide 7.55
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 All structures outside CNS
 Nerve = bundle of neuron fibers (usually
axons)
 Neuron fibers: bundled by connective
tissue (like muscles)

23. Structure of a Nerve
Slide 7.56
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 Endoneurium
surrounds each fiber
 Groups of fibers are
fascicles
Coverd by
perineurium
 Fascicles bound by
epineurium
Figure 7.20

24. Nerves (PNS) vs. Tracts (CNS)
Slide 7.54
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 Tract: a bundle of neuron fibers inside
the CNS
Usually axons
Wrapped by CT
Continuation of “nerve” from PNS
 Long tracts in spinal cord
 Short tracts in brain

25. Classification of Peripheral Nerves
Slide 7.57
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 Mixed nerves – both sensory and motor
fibers
 Afferent (sensory) nerves – carry
impulses toward the CNS
 Efferent (motor) nerves – carry impulses
away from the CNS

26. Cranial Nerves
Slide 7.58
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 Arise from brain
 12 pairs of nerves
 Numbered in order, anterior to posterior
 Most are mixed nerves, but three are
sensory only

27. Cranial Nerves
Slide 7.60
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 I Olfactory nerve – sensory for smell
 II Optic nerve – sensory for vision
 III Oculomotor nerve – motor fibers to
eye muscles
 IV Trochlear – motor fiber to eye
muscles

28. Cranial Nerves
Slide 7.61
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 V Trigeminal nerve – sensory for the
face; motor fibers to chewing muscles
 VI Abducens nerve –
motor fibers to eye muscles
 VII Facial nerve – sensory for taste;
motor fibers to the face
 VIII Vestibulocochlear nerve –
sensory for balance and hearing

29. Cranial Nerves
Slide 7.62
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 IX Glossopharyngeal nerve – sensory
for taste; motor fibers to the pharynx
 X Vagus nerves – sensory and motor
fibers for pharynx, larynx, and viscera
 XI Accessory nerve – motor fibers to
neck and upper back
 XII Hypoglossal nerve – motor fibers to
tongue