MUSCLE PHYSIOLOGY

Detailed explanation-1: -When the action potential reaches the end of the axon (the axon terminal), it causes neurotransmitter-containing vesicles to fuse with the membrane, releasing neurotransmitter molecules into the synaptic cleft (space between neurons).

Detailed explanation-2: -Apart from acetylcholine, other major neurotransmitters that the axon terminal provides a way across the synapse are dopamine, norepinephrine, epinephrine, serotonin, oxytocin, somatostatin, etc. These chemicals are important chemical regulators of many biological activities.

Detailed explanation-3: -At chemical synapses, presynaptic action potentials (APs) activate voltage-gated calcium channels, allowing calcium to enter and trigger neurotransmitter release. The duration, peak amplitude, and shape of the AP falling phase alter calcium entry, which can affect neurotransmitter release significantly.

Detailed explanation-4: -When an action potential, or nerve impulse, arrives at the axon terminal, it activates voltage-gated calcium channels in the cell membrane.