P.N.S.- Spinal Nerves Flashcards
What are spinal nerves attached to?
spinal cord
Are spinal nerves motor or sensory?
they are mixed- contain afferent and efferent neurons
How many pairs of spinal nerves are there and what are the regions?
31 pairs: 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
What is the function of a root?
attaches nerves to spinal cord
What are the 2 roots called?
- Dorsal Root = sensory and afferent (contains only sensory neurons)
- Ventral Root = motor and efferent (contains only motor neurons)
What do dorsal roots have that ventral roots do not?
Ganglia (called dorsal root ganglia) which is a collection of neuron cell bodies w/in the P.N.S.; it is 1st order meaning the 1st neuron in the pathway
What is a spinal nerve?
where roots come together
What are Branches (Rumus)?
They are mixed (both sensory and motor neurons)
Meningeal Branch
Dorsal (post.) Ramus: mixed
Ventral (ant.) Ramus: makes plexuses
White Rami Communicantes: A.N.S.
Gray Rami Communicantes: A.N.S
Sympathetic trunk ("chain") ganglion
What is a nerve plexus?
a network of interlaced nerves formed by ventral (ant.) rami
What is the Cervical Plexus?
C1-C5
main nerve: phrenic nerve - originates in neck and passes down b/w lungs and heart to reach the diaphragm
What is the Brachial Plexus?
C5-T1
main nerves:
radial - nerve that supplies the upper limb
medial - located in upper limb; only nerve that passes through the carpal tunnel
ulnar nerve - nerve which runs near ulna
What is the lumbar Plexus?
L1-L4
main nerve: femoral nerve - largest branch of lumbar plexus
What is the Sacral Plexus?
L4-S4
main nerve: sciatic nerve - large nerve that begins in the lower back and runs through buttock and down the lower limb
What is the function of spinal nerves?
spinal nerves are the path of communication b/w the spinal cord and a specific region of the body
What is a dorsal ramus and what does it do?
a dorsal ramus is a branch of each spinal nerve; it innervates certain parts of skin and muscles of the neck and back
