Muscles spindles - old stuff

Question 1

Innverbated by?

Answer 1

by α-motor neurons

Question 2

Contractile fibers of mm spindle

Answer 2

a. intrafusal muscle fibers

i. Innervated by γ-motor neurons

Question 3

Nuclear bag filaments

Answer 3

nuclei clumped together

Question 4

Primary ending?

Answer 4

A-α fiber (fast)

Question 5

response from primary ending?

Answer 5

dynamic

Question 6

Nuclear chain filaments

Answer 6

nuclei stacked

Question 7

Secondary endings

Answer 7

A-β fiber (slower)

Question 8

response from secondary endings

Answer 8

static

Question 9

Response?

Answer 9

i. Stretch –> immediate dynamic response from primary ending –> dynamic ending fires until stretch released –> new baselines are established & held by static response from secondary endings

Question 10

Alpha-gamma co-activation

Answer 10

as the α-motor neuron contracts to move the muscle, the γ-motor neuron is also activated to reset the muscle spindle –> maintain ideal length & effectiveness of spindle

Question 11

Golgi Tendon Organ:

Answer 11

sense tension on tendon

Question 12

GTO action?

Answer 12

GTO is sensitive to small changes in tension and sends AP’s to CNS when tension is present –> max firing rate = CNS shuts down α-motor neurons to protect mm (autogenic inhibition)

Question 13

GTO not influenced by?

Answer 13

a. patellar tendon reflex (deformation of tendon, not tension)