Neuromuscular System (Unit 3)

Question 1

Sarcoplasm?

Answer 1

Liquid interior of a muscle fiber

Question 2

Sarcoplasmic Reticulum?

Answer 2

Forms a network of channels that spread over the surface of the myofibril and stores/releases calcium ions to allow for muscle contraction

Use progressive overload to increase muscle fiber strength

Question 3

Slow Oxidative (Type I)?

Answer 3

Used in invasion games and long distance events

-Reaches peak force very slowly
-Energy Efficient
-High fatiguing tolerance
-Energy produced from aerobic pathways

E.g. A Marathon Runner

Question 4

Fast Twitch Muscle Fibers (Type II)?

Answer 4

-Reach peak force very quickly
-Generate a greater force of contraction
-Energy produced from anaerobic pathways
-Low fatiguing tolerance
-Larger diameter due to more/thicker myosin filaments

Question 5

Type II A?

Answer 5

Type II A are the oxidative glycolytic

-Used during short, high intensity endurance events e.g. 1500m in athletics
-Red meat in colour (large oxygen supply)

Question 6

Type II B?

Answer 6

Type II B are fast glycolytic

-They are used during high intensity, explosive events e.g. 100m in athletics
-White meat in colour (small oxygen supply)

Question 7

What is a Motor Unit?

Answer 7

A motor unit comprises of a motor neuron and its muscle fibers (small muscle fibers control precise movements, big muscle fibers control large movements with hundreds of fibers involved)

Question 8

What is a Motor Neuron?

Answer 8

A carrier of a nerve impulse, the more they travel the better the message, this then triggers the muscle fibers to contract (as long as the threshold is met)

Question 9

What is the Point where Neuron and Motor Unit Meet?

Answer 9

Its called the neuromuscular junction, where each motor unit of only one type of muscle fiber

Question 10

How does a Motor Unit cause Contraction?

Answer 10

-Impulse travels down the motor neuron
-Action potential is created (has to be strong enough)
-Impulse crosses the synaptic gap to the motor unit
-Impulse must be above the threshold for fibers to contract
-All fibers within the motor unit contract (All or None Law)

Question 11

All or None Law?

Answer 11

When a motor unit stimulates the muscle fiber, every muscle fiber in that unit then contracts, or doesn’t if the muscle unit threshold isn’t met

Question 12

What is Wave Summation?

Answer 12

The greater the frequency of stimuli, the greater the tension developed by the muscle, where a nerve impulse is repeated with no time to relax so a smooth, sustained contraction occurs, rather than twitches (tetanic contraction)

Question 13

What is Spatial Summation?

Answer 13

The strength of a muscular contraction varies depending on the number of motor units recruited. In order to achieve a greater force of contraction, the brain recruits bigger motor units. Rotating the frequency of the impulse to motor units delays fatigue and is called spatial summation

Question 14

What is Flexibility?

Answer 14

Range of movement at a joint

Question 15

What are the Benefits of being more Flexible?

Answer 15

-Reduced risk of muscular injuries
-Easier to get into complex positions
-Increased overall power
-Have a further reach

Question 16

What is Isometric?

Answer 16

Where a muscle doesn’t change length under tension e.g. plank (Abdominals)

Question 17

What is Isotonic?

Answer 17

The muscle changes length under tension

Concentric- Muscle shortens under tension
Eccentric- Muscle lengthens under tension

Question 18

What is Proprioneuromuscular Facilitation?

Answer 18

Uses an alteration between contraction and relaxation of muscles and is one of the most effective forms of flexibility training

Question 19

What is CRAC within Neuromuscular Propiofacilitation

Answer 19

Contract-Relax-Antagonist-Contract

Question 20

What are Muscle Spindles and How do they Cause the Stretch Reflex?

Answer 20

Muscle Spindles are proprioceptors that detect how far and fast a muscle is being stretched and produce the stretch reflex

They send an impulse to the nervous system, during PNF the muscles will either initiate a stretch reflex/ muscle contraction

Question 21

What is the Stretch Reflex?

Answer 21

The contraction of a muscle in response to over stretching (protect from injury)

In order to increase flexibility, the body part must be pushed further than the stretch reflex usually allows

Question 22

What are the Golgi Tendons

Answer 22

A sensor/ receptor found between the muscle and tendon that detects how much tension is being placed on the muscle

When activated it sends an inhibitory signal and causes a sudden relaxation of the muscle in response to high tension known as Autogenic Inhibition

This overrides the stretch reflex and causes the muscles to relax

Question 23

What is the Physiological Explanation of the PNF Process?

Answer 23

-Muscle spindles detect changes in muscle
-Cause stretch reflex
-Designed to protect against overstretching
-PNF overrides stretch reflex
-Golgi tendon organs activate and perform Autogenic Inhibition, muscles relax and allows for greater flexibility