1.3 Neuromuscular Systems

Question 1

What are the three main types of muscle fibres?

Answer 1

Type 1 (slow oxidative SO)
Type IIa (fast oxidative glycolytic FOG)
Type IIb (IIx) (fast glycolytic FG)

Question 2

What are some characteristic of Type 1 Slow Oxidative Twitch Fibres?

Answer 2

• Slow Twitch
• Red
• Resistant to fatigue
• Low force produced
• Produce energy aerobically

Question 3

What are some characteristics of Type IIa Fast Oxidative Glycolytic Twitch Fibres?

Answer 3

• Fast Oxidative
• Pink / Light Red
• More prone to fatigue
• Medium force produced
• Larger burst of energy is needed

Question 4

What are some characteristics of Type IIb (IIx) Fast Glycolytic Twitch Fibres?

Answer 4

• Fast Glycolytic
• White
• Rapid fatigue
• Highly explosive events
• Short burst of energy is needed

Question 5

Name a sporting example where Type 1 twitch fibres will benefit the performer?

Answer 5

Marathon runners

Question 6

Name a sporting example where Type IIa twitch fibres will benefit the performer?

Answer 6

Athletic events (400m, 800m, 1500m)

Question 7

Name a sporting example where Type IIb (IIx) twitch fibres will benefit the performer?

Answer 7

Athletic events (100m)

Question 8

Define aerobic?

Answer 8

Literally means ‘with oxygen’ so it refers to exercise that is low to medium intensity where the oxygen demand for muscles can be met.

Question 9

Define anaerobic?

Answer 9

Means ‘without oxygen’ and refers to exercise at high intensity such as sprinting, where the demand for oxygen by the muscles is so high that he cannot be met.

Question 10

Define hypertrophy?

Answer 10

Hypertrophy is where the muscle has become bigger and stronger?

Question 11

Explain a motor unit?

Answer 11

A motor neurone and it’s muscle fibres. Only one type of muscle fibre can be found in one particular motor unit. Muscle fibres work with the nervous system so that a contraction can occur. The motor neurone transmits the nerve impulse to the muscle fibre. Each motor neurone has branches that end in the neuromuscular junction on the muscle fibre.

Question 12

Fine motor neurones?

Answer 12

Nerve cells which transmit the brain is instructions as electrical impulses to the muscles.

Question 13

Define neuromuscular junction?

Answer 13

Where the motor neuron and the muscle fibre meet.

Question 14

Explain that all or none law?

Answer 14

Where a sequence of impulses has to be a sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. If not, none of them contract.

Question 15

Define wave summation?

Answer 15

Where there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction occurs, rather than twitches.

Question 16

Define tetanic contraction?

Answer 16

A sustained muscle contraction caused by a series of fast repeating stimuli.

Question 17

Define Spatial summation?

Answer 17

Where the strength of a contraction changes by altering the number and size of the muscles motor units.

Question 18

Define muscle spindles?

Answer 18

These detect how far and how fast a muscle has been stretched and produce the stretch reflex.

Question 19

Define Golgi tendon organs?

Answer 19

These are activated when there is tension in a muscle.

Question 20

Define isometric contraction?

Answer 20

Where there is tension in a muscle but no visible movement.

Question 21

Define autogenic inhibition?

Answer 21

Where there is a sudden relaxation of the muscle in response to high tension. The receptors involved in this process of Golgi tendon organs.