NMJ

An illustation of a neuromuscular junction, which is a synapse between a nerve axon and a muscle cell. Like other chemical synapses, there are vesicles of neurotransmitters (small green circles in this image) stored inside the terminal bouton of the presynaptic cell. When the electrical depolarization of an action potential reaches the terminal bouton, the vesicles fuse with the membrane of the presynaptic cell, spilling their neurotransmitter contents into the space between the two cells. The molecules of neurotransmitter passively diffuse across this space, and bind to receptors on the postynaptic membrane (shown here in red).