The Neuromuscular Junction

The ______ is where the motor neuron synapses with a muscle fiber.

neuromuscular junction

The contraction of a skeletal muscle begins when an action potential travels down the axon of a __________ to its axon terminal.

motor neuron

At the axon terminal, the action potential stimulates the opening of _________

voltage-gated calcium ion channels

The opening of these ion channels allows __________ ions to diffuse across the axon terminal membrane.

calcium

Calcium ions bind to __________ filled with __________, a neurotransmitter, causing them to fuse to the axon terminal membrane.

synaptic vesicles, acetylcholine

Fusion to the axon terminal membrane causes the synaptic vesicles to release acetylcholine into the __________, which is a gap between the axon terminal membrane and sarcolemma.

synaptic cleft

Once in the synaptic cleft, acetylcholine binds to a __________, causing it to open and allowing __________ ions to diffuse across the __________, or postsynaptic membrane.

chemical gated sodium ion channel, sodium, sarcolemma

Diffusion of sodium ions across the sarcolemma creates another __________.

action potential