What happens when an action potential reaches the presynaptic terminal of the motor neuron?

Question

Quizplus · Accepted Answer

When an action potential reaches the presynaptic terminal of the motor neuron, voltage-gated calcium channels open, allowing calcium ions to flow into the synaptic terminal. This triggers the release of the neurotransmitter acetylcholine into the synaptic cleft. The acetylcholine molecules then bind to receptors on the muscle fibre, causing an influx of sodium ions and depolarization of the muscle cell membrane, which leads to muscle contraction.

What Happens When an Action Potential Reaches the Presynaptic Terminal