Muscle Reflexes

Question 1

Muscle spindle

Answer 1

Spindle around the muscle that activates when a muscle is stretched; stretch reflex.

It is contracted by the gamma motor neuron during voluntary movement so they stay short enough to sense stretching, even when muscles are short

Question 2

The Stretch reflex

Answer 2

Muscle spindle senses a stretch, this activates the AMN through the sensory (dorsal) root. The muscle contracts

Very important in maintaining posture (have to keep muscle at right tone)

Question 3

Reciprocal inhibition

Answer 3

If a agonist muscle is contracted due to the reflex, the antagonist has to be inhibited (opposite muscle)

Extensor muscles (muscles to extend) contract, flexor muscles relax (and vice versa if you flex)

aka antagonistic relaxation

Question 4

Crossed extensor reflex

Answer 4

One limb flexes, the other extends. The neurons on the other side respond in opposite manner. (retract one leg, the other extends)

Question 5

Central Pattern Generator

Answer 5

Cat experiment, paralysed but it’ll start to walk/run. The generator creates locomotion on its own, you just need a gait command (proprioceptive feedback)

Similar for:
Swallowing
Breathing
Orienting

Question 6

Withdrawal reflex

Answer 6

Reflex when pain is sensed. You react before realizing you’re hurt. Protection reflex

Question 7

Golgi Tendon reflex

Answer 7

The Golgi tendon organ sits in the tendons. They don’t really stretch, but if they do the golgi tendon reflex causes your muscle to relax and drop the load. Otherwise you’d snap the tendon.