DIRT from Roberts muscles and synapses test

Question 1

explain the importance of reflex actions (3 marks)

Answer 1

• they are an involuntary response
• prevents damage to tissues (e.g: burning)
• role in homeostasis (insulin/glucagon)
• maintain posture and balance

Question 2

an action potential is generated at the cell body of a motor neurone

explain how this action potential passes along the motor neurone to the neuromuscular junction ( 3 marks)

Answer 2

1. influx of Na+ causes depolarisation
2. Na+ diffuse along axon causing v.g Na+ channels to open
3. causes more Na+ ions to move in causing further depolarisation

Question 3

explain why explosive exercises such as sprinting and weightlifting will be more affected by this muscle loss than aerobic exercise e.g: jogging
(1 mark)

Answer 3

fast twitch muscle fibres

Question 4

list 3 differences between a cholinergic synapse and a neuromuscular junction

Answer 4

1. neurone to neurone and neurone to muscle;
2. no summation in muscle;
3. muscle response always excitatory (never inhibitory);
4. some neuromuscular junctions have different neurotransmitters;