Spinal Nerves Flashcards
what is the structure of a spinal nerve
roots
spinal nerve
rami of spinal nerves
what is the spinal nerve
formed by a union of dorsal and ventral roots
2 way street (both sensory and motor info flows through)
what are roots
roots are one way, either dorsal or ventral
what are the rami of the spinal nerves
either dorsal ramus or ventral ramus
what is the dorsal root
one way street (carries only afferent fibers to CNS, sensory info)
attached to dorsal root ganglion
what is the dorsal root ganglion
contains cell bodies of afferent neurons
what is the ventral root
carries only efferent info to the PNS (motor information)
where is the nucleus for ventral nerve cell bodies found
spinal cord
what is the dorsal ramus
2 way street
only carries info to the deep muscles of the back and the skin that covers these muscles
what is the ventral ramus
2 way street
carries info to the extremities and front of the body
what is a large motor unit
one axon innervates 100-1000s of muscle cells
for power
what is a small muscle unit
one axon innervates 3-5 fibers
for fine control
