Neuromuscular

Question 1

what is a motor unit?

Answer 1

a single alpha neuron and all the muscle fibres it innervates

Question 2

what is a motor end plate?

Answer 2

the portion of plasma membrane of the muscle fibre that lies directly under the axon terminal

Question 3

what is the function of the golgi tendon organ?

Answer 3

to measure the tension going through a muscle either from passive stretch or muscle contraction

Question 4

where are golgi tendon organs located?

Answer 4

afferent nerve fibres wrap around collagen fibres at the junction between muscle and tendon

Question 5

how is tension transduced in the golgi tendon organ?

Answer 5

tension in the muscle straightens the collagen fibers of the golgi tendon organ this distorts the 1b afferent nerve fiber endings generating action potentials

Question 6

activation of the golgi tendon organ causes what?

Answer 6

Sensory afferents synapse with an interneurone which causes

• inhibition of contracting muscle
• inhibition synergistic muscles
• stimulates the contraction of antagonistic muscles

Question 7

why do we have golgi tendon organs?

Answer 7

to protect muscle and connective tissue from injury

Question 8

what is the function of the muscle spindle?

Answer 8

it measures the amount of stretch in a muscle

Question 9

where is the muscle spindle located? and what is is comprised of?

Answer 9

afferent sensory fibers are wrapped around intrafusal fibers that are innervated by gamma motor neurons which keep the fibres at a set length best for stretch detection

Question 10

activation of the muscle spindle leads to what?

Answer 10

• stimulates contractions of felxor muscle (muscle stretch is detected in)
• stimulates contraction of synergistic muscles
• inhibits contraction of extensor/antagonistic muscles (via interneurone)

Question 11

describe what happens in a stretch reflex?

Answer 11

afferent sensory fibers detect stretch in the intrafusal muscle fibres and sends impulses to the spinal which causes the contraction of flexor and synergistic muscles afferent also synapses with an interneurone inhibits contraction of antagonistic extensor muscles

Question 12

what is the inverse stretch reflex?

Answer 12

take takes place when a golgi tendon organ is activated

Question 13

what happens in the withdrawal reflex?

Answer 13

a cutaneous stimuli causes flexion of one leg and extension of the other leg

Question 14

what is the knife clasp reflex?

Answer 14

in a neurological examination thereis initial resistance to the movement of a limb and then a sudden giving way to movement

typical of upper motor neuron damage

Question 15

what are expected symptoms with lover motor neuron damage?

Answer 15

• decreased tone
• muscular atrophy
• diminshed or absent reflexes
• babinski sign & fasciculations present

Question 16

what are the expected symptoms with upper motor neuron damage?

Answer 16

• increased tone
• non to little muscular atrophy
• hyperactive reflexes
• babinski sign and fasciculations not present