Neuromuscular System - TOPIC 1

Question 1

what are trained muscle fibres called?

Answer 1

type IIx

Question 2

What do muscle spindles do?

Answer 2

Detect muscles being stretched and causes the muscle to contract (stopping the muscle stretching to far)

Question 3

What do Golgi tendons do?

Answer 3

Detect tension in the muscle during an ISOMETRIC contraction and cause the muscle to relax and LENGTHEN. This means the muscle can stretch further

Question 4

What is a motor unit?

Answer 4

a motor neurone and its muscle fibres

Question 5

What are motor neurones?

Answer 5

Nerve cells which transmit the brains instructions as electrical impulses to the muscle

Question 6

What is a neuromuscular junction?

Answer 6

the point where the motor neurone and muscle fibres meet

Question 7

What is the all or none law?

Answer 7

impulses arriving at the neuron must meet a minimum level, if they do all of the muscles in the motor unit will contract. If not then no muscles will contract

Question 8

What is wave summation?

Answer 8

repeated nerve impulse which doesn’t allow the muscle fibres time to fully relax, causing a tetanic contraction

Question 9

What is a tetanic contraction?

Answer 9

a smooth sustained muscle contraction (not a twitch)

Question 10

What is spatial summation?

Answer 10

when the strength of contraction changes by altering the number and size of muscle motor units being recruited

Question 11

Two stages of spatial summation?

Answer 11

FIRSTLY: if more force is needed, then the body can recruit additional motor units to develop more force

SECOND: for endurance, our body can delay fatigue of muscle fibres by altering the motor units used.