(S1W2) Control of Muscle Activation part 7

Question 1

Used a T-reflex (tendon reflex) example to show the muscle spindle doing its’ job

Answer 1

• patella tendon reflex test
• doctor taps patella tendon at your knee
• when tapped, quadricep muscle lengthens quickly and muscle spindle senses this
• so quadricep stimulated to contract to shorten, extending your leg

Question 2

Why is the T-reflex the quickest in the body?

Answer 2

• autogenic, meaning muscle stimulates itself
• monosynaptic, meaning only one synapse
• every time you add another layer of complexity or another synapse, you’re adding about 0.5 ms

Question 3

How long does a T-reflex (tendon reflex) take?

Answer 3

about 30 ms

Question 4

Delays in T-reflex

Answer 4

• time for afferent signal to go from muscle spindle to central nervous system
• central delay
• time for efferent signal to reach muscle

Question 5

What route does the sensory information take out of the muscle spindle?

Answer 5

• signal from the muscle spindle
• along Ia afferent neuron
• through the dorsal route

Question 6

What route does the efferent signal take back to the muscle to act on the sensory information during a T-reflex (tendon)?

Answer 6

• through the ventral route
• along an alpha ⍺ motoneuron to the muscle

Question 7

What are the two routes within the spinal cord?

Answer 7

• dorsal route - posterior (at the back) - where all your sensory information comes in
• ventral route - anterior (at the front) - where all of your efferent information goes out