<P> When a motor neuron generates an action potential , it travels rapidly along the nerve until it reaches the neuromuscular junction , where it initiates an electrochemical process that causes acetylcholine to be released into the space between the presynaptic terminal and the muscle fiber . The acetylcholine molecules then bind to nicotinic ion - channel receptors on the muscle cell membrane , causing the ion channels to open . Calcium ions then flow into the muscle cell , initiating a sequence of steps that finally produce muscle contraction . </P>
<P> When a motor neuron generates an action potential , it travels rapidly along the nerve until it reaches the neuromuscular junction , where it initiates an electrochemical process that causes acetylcholine to be released into the space between the presynaptic terminal and the muscle fiber . The acetylcholine molecules then bind to nicotinic ion - channel receptors on the muscle cell membrane , causing the ion channels to open . Calcium ions then flow into the muscle cell , initiating a sequence of steps that finally produce muscle contraction . </P>
where is acetylcholine released from to stimulate muscle contraction
where is acetylcholine released from to stimulate muscle contraction
the neuromuscular junction
the neuromuscular junction