<P> The neuromuscular junction is where a neuron activates a muscle to contract . Upon the arrival of an action potential at the presynaptic neuron terminal , voltage - dependent calcium channels open and Ca ions flow from the extracellular fluid into the presynaptic neuron 's cytosol . This influx of Ca causes neurotransmitter - containing vesicles to dock and fuse to the presynaptic neuron 's cell membrane through SNARE proteins . Fusion of the vesicular membrane with the presynaptic cell membrane results in the emptying of the vesicle 's contents ( acetylcholine ) into the synaptic cleft , a process known as exocytosis . Acetylcholine diffuses into the synaptic cleft and can bind to the nicotinic acetylcholine receptors on the motor endplate . </P>
<P> The neuromuscular junction is where a neuron activates a muscle to contract . Upon the arrival of an action potential at the presynaptic neuron terminal , voltage - dependent calcium channels open and Ca ions flow from the extracellular fluid into the presynaptic neuron 's cytosol . This influx of Ca causes neurotransmitter - containing vesicles to dock and fuse to the presynaptic neuron 's cell membrane through SNARE proteins . Fusion of the vesicular membrane with the presynaptic cell membrane results in the emptying of the vesicle 's contents ( acetylcholine ) into the synaptic cleft , a process known as exocytosis . Acetylcholine diffuses into the synaptic cleft and can bind to the nicotinic acetylcholine receptors on the motor endplate . </P>
as a result of ach stimulation calcium ions are released from the
as a result of ach stimulation calcium ions are released from the
the extracellular fluid
the extracellular fluid