Organization of spinal nerves

central nervous system

brain and spinal cord

peripheral nervous system

all nervous structure outside of CNS (including nerves)

how are the CNS and PNS arranged?

bilaterally symmetric and segmentally arranged

how many segments of tissue form the trunk and limbs

31 segments of tissue

the spinal cord has how many segments

31

each sinal cord segment has paired what?

spinal nerves that innervate each trunk/limb segment

the brain has paired what?

cranial nerves that innervate muscles and skin of the head and neck

neuron

cell type for the nervous system

multipolar neuron

motor neurons

pseudounipolar neuron

sensory neurons

ganglion

collection of cell bodies

which system is the dorsal root ganglion in

PNS

nerve

axons of multiple neurons traveling together to/from target

most nerves carry what

motor and sensory axons

how many pairs of spinal nerves innervate the trunk and limbs

31 pairs of spinal nerves

one pair of spinal nerves innervates what?

one segment of the trunk or limb

spinal nerves contain how many axon / fiber types

3 axon / fiber types

3 axon / fiber types:

somatomotor, sympathetic (visceromotor), somatosensory 

somatomotor

innervation from CNS to skeletal muscle within segment

sympathetic (visceromotor)

innervation from CNS to smooth muscle and sweat glands within segment

somatosensory

information from segment of skin (pain, touch, temperature) to CNS

name the nerves

posterior cutaneous nerve, lateral cutaneous nerve, anterior cutaneous nerve, ventral ramus, dorsal ramus, spinal nerve

cutaneous nerves contain what two fiber types

sympathetic and somatic

spinal nerves, dorsal rami, ventral rami contain…

3 fiber types

somatomotor target

skeletal muscle of trunk and limbs

sympathetic target

smooth muscle, blood vessels, and glands in skin

somatosensory target

sensory receptors in skin (pain, touch, temperature)

T4

nipple line

T10

umbilical line

T12

pelvic line

dermatome

stip of skin supplied by one spinal nerve pair

3 dermatomes with clinical significance

T4, T10, T12

shingles caused by

herpes zoster that caused chicken pox

herpes zoster attacks the…

somatosensory cell bodies at one spinal level

shingles results in…

rash in the dermatome innervated by infected somatosensory neurons