Motor Sensory Junctions

Question 1

How many cell types are seen at the NMJ?

Answer 1

Three: motor neuron, muscle fiber, schwann cells

Question 2

where does axon innervate a muscle fiber

Answer 2

center protion

Question 3

what causes teh knee jerk refklex?

Answer 3

Ia spindle afferents from ya quads

Question 4

muscle spindle structure composition

Answer 4

intrafusal fibers: nuclea bag fibers and chain fibers

Question 5

How do motor neurons get to skeletal muscle

Answer 5

via branching

Question 6

what do teh afferent spindles send to teh brain?

Answer 6

Ia sends info, type II sends info of length

Question 7

muscle spindle function

Answer 7

stretch

Question 8

are many muscle fibers always innervated by oen axon?

Answer 8

No. Postnatally yes, synaptic elimination allows for all but one axon to remaina and innervate the NMJ.

Question 9

what is a muscle fiber innervated by

Answer 9

one motor neuron that can branch to multiple fibers

Question 10

structure of golgi tendon

Answer 10

ia afferent nerve endings with collagen to allow for a protective reflex. For protection

Question 11

what are teh sensory receptors in skeletal muscle?

Answer 11

spindle and the golgi tendon

Question 12

Where are cell bodies located for perpheral nerves?

Answer 12

in the spinal chord, but in the nerve itself out the CNS

Question 13

Innervation of spindle

Answer 13

affert and efferet, where efferent is what contracts for sense(motor)

Question 14

Golgi tendon lcoation and function

Answer 14

myotendenous junction, tension/contraction

Question 15

identify

Answer 15

AchR

Question 16

Answer 16

AchR, nerve, schwann cells

Question 17

Where does each cell type in the NMj derive from?

Answer 17

muscle fiber: myoblasts via somites, motor axon via neural tube, schwann cells via neural crest.