A and P chapter 13b spinal nerves and reflexes Flashcards
(100 cards)
what is a nerve?
a bundle of axons (both myelinated and unmyelinated) that is enclosed ina connective tissue sheath
whats the difference between nerve and neuron
nerve=organ
neuron=cell
what are the nodes of ranvier
exposed part of an axon that allows for saltatory conduction
which type of nerve bundle transmits peripheral to the CNS
sensory (affarent) nerves
which type of nerve bundle transmits from the CNS to peripheral
motor (efferent) nerves
what are mixed nerves
have both motor and sensory nerves
name the 4 types of nerves you can find in a mixed nerve
somatic efferent (motor)
somatic affarent (sensory)
autonomic efferent
autonomic afferent
what are ganglia and where are they found
cluster of neuron cell bodies in the PNS
why are there so many cell bodies in ganglia
protection in numbers and allows for connection between pathways
where do C1 to C7 nerves emerge
above the vertebae
where do C8 nerve emerge
between C7 and T1 (below C7)
where do nerves from T1 down emerge from
emerge below the vertebrae and so forth
what is spinal root?
where rootlets from spinal cord or ganglia merge
What is a ramus?
initial branches off a nerve
what is a dorsal root?
merges with posterior horn gray matter and has sensory fibers that form the dorsal root ganglia
what is a ventral root?
motor fibers from anterior horn gray matter to skeletal muscle and autonomic NS fibers
What anatomical features are special to T2-L1
communicating rami connecting the sympathetic chain ganglion to the spinal nerve
what virus remains in the posterior root ganglia for life and how can it spread to cause a continuing disease process
zoster virus/chickenpox. Can migrate to other layers of sensory nerves when immune system is compromised and causes shingles
what is the difference between a root and a rami?
a root connects the spinal nerve to the spinal cord and the rami do not connect to the spinal cord
what is a dermatome
cutaneus branch representation of a single spinal nerve; sensory branch of single spinal nerve that covers some strip of body and doesn’t overlap (completely anyway)
what does a dermatome of the trunk look like
transverse strips of mostly uniform width
If the arm dermatomes are affected, which nerves are in question
C5-T1
if the leg dermatomes are affected, which nerves are in question
lumbosacral nerves
what is a nerve plexus
group of nerves that serve a particular region