21. Neuromuscular Control of Muscle Contraction

What is the primary function of a nerve impulse in the nervous system?

• To store genetic information

• To transmit signals along neurons

• To produce hormones

• To digest nutrients

What is the name of the gap between a motor neuron and a muscle fibre?

• Axon hillock

• Myelin sheath

• Node of Ranvier

• Synaptic cleft

Which neurotransmitter is released at the neuromuscular junction to stimulate muscle contraction?

• Dopamine

• Serotonin

• Acetylcholine

• Adrenaline

What is the correct order of events during the transmission of a nerve impulse across a synapse?

• Neurotransmitter release → Action potential arrives → Receptors activated

• Action potential arrives → Neurotransmitter release → Receptors activated

• Receptors activated → Action potential arrives → Neurotransmitter release

• Neurotransmitter release → Receptors activated → Action potential arrives

Which enzyme breaks down acetylcholine in the synaptic cleft?

• Amylase

• Acetylcholinesterase

• Lipase

• Pepsin

What is the effect of acetylcholine binding to receptors on the muscle fibre membrane?

• Muscle fibre relaxes

• Muscle fibre dies

• Muscle fibre divides

• Muscle fibre contracts

Which part of the neuron carries the action potential away from the cell body?

• Dendrite

• Axon

• Synaptic cleft

• Nucleus

What is the term for the minimum level of stimulation required to trigger an action potential?

• Threshold

• Maximum

• Limit

• Plateau

Which of the following best describes the direction of a nerve impulse?

• From muscle to neuron

• From dendrite to axon terminal

• From axon terminal to dendrite

• From synaptic cleft to cell body

What is the role of the myelin sheath in nerve impulse transmission?

• It insulates the axon and speeds up transmission

• It slows down the impulse

• It stores neurotransmitters

• It produces action potentials