Musclular System

Question 1

Function of muscular system?

Answer 1

Create movement

Question 2

What are agonist, antagonist and fixator?

Answer 2

Agonist-muscles responsible for movement at joint (prime mover)
Antagonist-muscles that opposes agonist providing resistance
Fixator-muscle that stabilises one part of a body while another causes movement

Question 3

What are the types of contractions?

Answer 3

• Isotonic-concentric and eccentric

* Isometric

Question 4

What are isotonic muscle contractions?

Answer 4

Where the muscles changes length during contraction, happens in 2 ways:

1) concentric- muscle gets shorter, force pulls 2 bones together
2) eccentric- muscle gets longer during contraction, resists force to control joint movement

Question 5

What is an isometric contraction?

Answer 5

Where muscle contracts but do not change lengthy creates tension and pulls on tendon

Question 6

Role of motor unit?

Answer 6

1) nerve impulse is initiated in the motor neurone cell body
2) nerve impulse conducted down the axon of the motor neurone by a nerve action potential to the synaptic cleft
3) neurotransmitter called ‘acetylcholine’ (ach) is secreted into the synaptic cleft
4) if the electrical change is above the threshold, the muscle fibres contract (happen in an ‘all or none’ fashion)

Question 7

What is the all or none law?

Answer 7

When a motor unit receives a stimulus & creates an action potential that reaches a threshold charge. All muscles fibres within the motor unit will contract at the same time with maximum force.

Question 8

What are slow twitch fibres?

Answer 8

• Designed for aerobic exercise
• Use oxygen to produce a small amount of tension over a long period of time
• very resistant to fatigue due to slow contraction
• have a higher capacity of aerobic respiration
• red in colour because of more myoglobin
• endurance athletes have high %

Question 9

What are Fast Oxidative Glycolytic Fibres (type 2a)?

Answer 9

• for anaerobic respiration
• more resistant to fatigue than type b
• generate less force than type 2b
• athletes in 200m swim Orr 800m rely on type 2a

Question 10

What are Fast Twitch Glycolytic Fibres (type 2b)?

Answer 10

• have the greatest anaerobic capacity
• generate the largest amount of force of contraction
• very poor resistance to fatigue
• sprinters or shot putter have large amounts of FTG fibres