PNS practicle 2

Question 1

what happens if there is a lesion in the ventral root

Answer 1

reduced sensation from that dermatome - not really noticeable because dermatome still gets signals from other spinal layers

Question 2

what happens if there is a lesion in the ventral root

Answer 2

muscle weakness in the myotome - still get some signal from other spinal layers

Question 3

what happens if there is a lesion in the spinal nerve

Answer 3

reduced sensory effect and weakness in myotome

Question 4

what happens id there is a lesion in the nerve after the plexus

Answer 4

no sensation/paralysis in area - no other nerves innovate the tissue

Question 5

what is the function of the node of ranvier

Answer 5

point where ap is propagated
where the Na channels are
allow saltatory conduction - so fast velocity of nerve impulses

Question 6

how can you tell whether demyelination occurred because of nerve crushing/ neuropathy

Answer 6

if demyelination constant - nerve crushing

in neuropathy - demyelination would be random

Question 7

how can you tell a nerve is regenerated not normal

Answer 7

has non-specific myelination of 1 axon

shwann cells are smaller than in normal neurons

Question 8

how can you tell a neuron is regenerating

Answer 8

sprouting comes off axon - trying to find way back to original muscle
one sprout is then selected and is myelinated