Synaptic Junction - Release of Acetylcholine to across the Junction / Single Project

An image of the synaptic junction, the place where a nerve impulse passes from on neuron to the next. In this example, the neuromuscular junction the motor neuron synapses with the targeted muscle cell. The action potential (electrical impulse) moves along the motor neuron carries the depolarization wave to the terminal buttons of the presynaptic neuron. Once at this terminal, depolarization at the junction causes the release of acetylcholine (in red) at the presynaptic vesicle.

Absorption of acetylcholine at the postsynaptic junction by the nicotinic acetylcholine receptors generates associated ion channels to transport sodium across the membrane. This influx of electropositive ions locally depolarizes the postsynaptic muscle cell membrane in turn leading to a release of calcium ions from the sarcoplasmic reticulum. The ensuing mass-scale depolarization of the cell, a consequence of calcium ion release, initiates muscle contraction

Revised in 2013.