Peripheral Nervous System

Question 1

what is the PNS composed of

Answer 1

anything outside the CNS

has 2 parts (somatic and autonomic)

Question 2

how many pairs of cranial nerves are there

Answer 2

12 pairs of cranial nerves

Question 3

how are the spinal nerves organized

Answer 3

8 pairs of cervical spinal nerves

12 pairs of thoracic

5 pairs of lumbar

5 pairs of sacral

1 pair of coccygeal

Question 4

cervical spinal nerves

Answer 4

first pair comes out above C1

nerve numbers are based upon the cervical vertebrae they come out above of

C8 comes out below C7

Question 5

thoracic spinal nerves

Answer 5

come out below the vertebrae they are named after

Question 6

lumbar spinal nerves

Answer 6

come out below the vertebrae they are named after

Question 7

sacral spinal nerves

Answer 7

named after the segment they come out below off

Question 8

coccygeal spinal nerves

Answer 8

comes out below the coccyx

Question 9

what are ganglion

Answer 9

collection of nerve cell bodies in the PNS (same as a nucleus in the CNS)

Question 10

what are the structure of peripheral nerves

Answer 10

schwann cells and 3 layers of connective tissue

Question 11

what are schwann cells

Answer 11

produce sheaths that surround individual axons

large diameter fibers –> myelinated

small diameter fibers –> unmyelinated

Question 12

what are the 3 layers of connective tissue

Answer 12

endoneurium –> around a single axon

perineurium –> around bundles of axons (fascicles), small blood vessels found

epineurium –> surrounds all fascicles, small blood vessels found