Spinal Reflexes

Question 1

ventral horn contains what

Answer 1

motor neurons

Question 2

what do alpha motor neurons look like

Answer 2

large

prominant cell body

Question 3

what do alpha motor neurons give rise to

Answer 3

axons that end in skeletal muscle

Question 4

what do gamma motor neurons look like

Answer 4

smaller

smaller size cell body

Question 5

what do gamma motor neurons give rise to

Answer 5

axons that run along with alpha motor neurons, terminante in muscle

Question 6

what do gamma motor neurons innervate

Answer 6

polar ends of intrafusal fibers located insid emuscle spindles

Question 7

what are muscle spindles

Answer 7

stretch receptors

Question 8

what do alpha motor neurons innervate

Answer 8

skeletal muscle

Question 9

spinal reflex reaction

Answer 9

simple stereotyped response to a specific sensory stimulus

Question 10

where is the cell body of a pseudounipolar neuron located

Answer 10

inside dorsal root ganglia

Question 11

where is the motor neuron cell body located

Answer 11

ventral body of spinal cord

Question 12

what does motor neuron form

Answer 12

efferent or motor limb of reflex arc

Question 13

muscle spindles are unique to what

Answer 13

skeletal muscle

Question 14

where are intrafusal muscle fibers located

Answer 14

centrally inside the fusiform structure known as muscle spindle

Question 15

what are the 2 types of intrafusal muscle fibers

Answer 15

nuclear bag fiber, nuclear chain fiber

Question 16

nuclear bag fiber

Answer 16

have central, noncontractile, bag like strucutre containing many nuclei

Question 17

what do nuclear bag fibers get innervation

Answer 17

gamma neurons
Ia
II

Question 18

nuclear chains

Answer 18

have noncontractile component and contractile component

Question 19

what innervates contractile component of nuclear chain

Answer 19

gamma motor neurons
Ia
II

Question 20

what innervates extrafusal fibers

Answer 20

alpha motor neurons

pseudounipolar neurons

Question 21

what do intrafusal fibers receive sensory innervation from

Answer 21

annulospinal endings

Question 22

reciprocal inhibition

Answer 22

extension of and enhances stretch reflex (can’t have quad. femoris and hamstrings contraction happening at the same time)

Question 23

autogenic inhibition

Answer 23

enhances stretch reflex, prevent over=contraction of skeletal muscle

Question 24

flexor (withdrawl, nociceptive) reflex

Answer 24

protects affected limb from noxious stimulus

Question 25

cross-extension reflex

Answer 25

supports the body and balance as weight is shifted from the affected limb to unaffected limb

Question 26

muscle stretch reflex

Answer 26

protects muscles from overstretching

Question 27

functino of gamma motor neuron

Answer 27

maintain muscle tone via gamma loop

Question 28

function of alpha gamma co-activation

Answer 28

maintains teh sensitivity of the muscle spindles as effective stretch receptors regardless of muscle length

Question 29

function of alpha gamma co-activation

Answer 29

maintains teh sensitivity of the muscle spindles as effective stretch receptors regardless of muscle length

Question 30

C fiber

Answer 30

unmyelinated

Question 31

alphadelta fiber

Answer 31

slightly myelinated

Question 32

muscle tone

Answer 32

muscle tension

Question 33

gamme motor neurons are under ______ controle

Answer 33

supraspinal

Question 34

how is cerebellum involved in coordination of movement

Answer 34

recieve sensory info about orientation and position of body parts
use info to make adjustments to impending movement
produces muscle tone

Question 35

basal ganglia

Answer 35

inhibit excess muscle tone

Question 36

what happens if you don’t have gamma motor neurons

Answer 36

intrafusal fibers are ineffective stretch receptors - become slouchy

Question 37

what happens in a lower motor neuron lesion

Answer 37

gamma and alpha motor neurons are damaged. muscle becomes deneravted

Question 38

flaccid paralysis of denervated muscle is caused by

Answer 38

no electricle signals from CNS