nervous system: pns structures

Question 1

structures

Answer 1

spinal nerves

cranial nerves

Question 2

cranial nerves

Answer 2

12 pairs in total

go to page 13

Question 3

cranial regions I and II

Answer 3

forebrain

Question 4

cranial regions III and IV

Answer 4

midbrain

Question 5

cranial regions V to VIII

Answer 5

pons

Question 6

cranial regions IX to XII

Answer 6

medulla oblongata

Question 7

2 pairs

Answer 7

only sensory neurons

I and II

Question 8

1 pair

Answer 8

mainly sensory

VIII

Question 9

9 pairs

Answer 9

mixed nerves

• carry both sensory and motor neurons
  (eg. trigeminal V
• motor function=chewing
• sensory function =conveys general sensations (touch, pressure, pain, temp etc) from face to CNS

Question 10

motor neurons

Answer 10

cell bodies in brainstem nuclei

Question 11

sensory neurons

Answer 11

cell bodies in ganglia of PNS

Question 12

Spinal nerves

Answer 12

31 pairs- all mixed nerves
-exit by intervertebral foramina (except 1st- b/w atlas and an occipital bone)
-each has 2 points of attachment to spinal cord:
dorsal root and ventral root

Question 13

31 pairs

Answer 13

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 14

dorsal root

Answer 14

sensory; cell bodies in dorsal root ganglion

Question 15

ventral root

Answer 15

autonomic and somatic motor neurons; cell bodies in ventral or lateral horn

Question 16

spinal nerve

Answer 16

joining of dorsal and ventral roots
-immediately divides into branches = rami:
dorsal ramus and ventral ramus and rami communicantes

Question 17

dorsal ramus

Answer 17

innervates skin and muscles of back

Question 18

ventral ramus

Answer 18

forms thoracic nerves (T2-T12) or further branch and join up forming nerves plexuses (=nerve networks)
-spinal nerve plexus

Question 19

spinal nerve plexus

Answer 19

page 14-15

Question 20

rami communicantes

Answer 20

connects ventral ramus to sympathetic trunk

contain autonomic nerve fibres (neurons)

Question 21

cross section of nerve

Answer 21

axon and fascicle

• epineurium-around whole nerve (CT)
• perineurium -around fascicles (CT)
• endoeurium around axon and myelin (CT)