The Peripheral Nervous System PNS

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The Peripheral Nervous System PNS Powered By Docstoc
					   The Peripheral Nervous
       System (PNS)
31 pairs of spinal nerves and 12 cranial nerves
                outside the CNS
I. Spinal Nerves
Lead to and from the spinal cord
Plexuses- “braid”, cluster of nerves
   except T2-T12
     I. Spinal Nerves
A. Cervical / brachial plexus- 8 nerves
     around the 7 cervical vertebrae
B.   Thoracic- 12 nerves around 12 thoracic
     vertebrae; not a plexus
C.   Lumbar- 5 nerves around 5 lumbar
     vertebrae; cauda equina- horse tail
D.   Sacral plexus- 5 nerves around sacrum
E.   Coccygeal nerve- 1 nerve around
I. Spinal Nerves
F. 13 Spinal Nerve
   Branches To Know:
   1. Phrenic- diaphragm
   2. Axillary- circumflex
   3. Ulnar- arm and hand
      muscles; senses
   4. Median-
   5. Radial-
   6. Pudendal- perineal
      muscles in genitalia,
I. Spinal Nerves
F. 13 Spinal Nerve Branches To Know:
   7. Femoral- leg muscles
   8. Lateral Femoral Cutaneous- senses of thigh
   9. Saphenous- towards patella, senses
   10. Sciatic- largest nerve- ¾ in diameter, back thigh, muscles
   11. Tibial- off sciatic, lower leg, senses
   12. Common Peroneal- leg and foot muscles, senses
   13. Medial Cutaneous- lower leg, senses
II. Cranial Nerves
Consist of bundles of axons
Named based on primary function or structure that
  they serve
A. Three Kinds- sensory, motor, mixed
II. Cranial Nerves
                                     I. Olfactory
B. Cranial Nerves to Know:
  I. Olfactory- smell- S             II. Optic

  II. Optic- vision- S               III. Oculomotor
  III. Oculomotor- eye mover- M
                                     IV. Trochlear
  IV. Trochlear- eye mover- M
  V. Trigeminal- largest, chewing,   V. Trigeminal
     sensation-B                     VI. Abducens
  VI. Abducens- eye mover-M          VII. Facial
  VII. Facial- taste, tears- B
 II. Cranial Nerves
B. Cranial Nerves to Know:       VII. Vestibulocochlear

    hearing, balance- S           IX. Glossopharyngeal

  IX- Glossopharyngeal- taste,
    moves tongue- B
                                     X. Vagus
  X- Vagus- thoracic and
    abdominal cavities- B           XI. Accessory

  XI- Accessory- helps vagus
    nerve, larynx, pharynx,
    upper shoulder muscles- M
                                 XII. Hypoglossal
  XII- Hypoglossal-moves
    tongue- M
II. Cranial Nerves

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II. Cranial Nerves
    Motor, or Both-

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III. Two Divisions of the PNS
A. Somatic Nervous System (SNS)
  1. Regulates voluntary effectors to carry signal to the
  2. Regulates skeletal muscles
  3. Somatic Motor Pathway-
    brain or SC  single motor neuron with myelin 
    synapse with Ach  skeletal muscle
III. Two Divisions of the PNS
B. Autonomic Nervous System (ANS)
  1. Regulates involuntary effectors to carry signals to
  2. Regulate cardiac muscle, smooth muscle, and
    glandular epithelial tissue
  3. 2 Divisions
     A. Sympathetic Division- Flight or Fight
     B. Parasympathetic Division- Rest and Repair