MUSCLE PHYSIOLOGY

Detailed explanation-1: -Muscle contraction is controlled by receptors in the muscle cell membranes that respond to the neurotransmitter acetylcholine when it is released from motor neurons.

Detailed explanation-2: -In skeletal muscle, the parasympathetic nervous system releases acetylcholine neurotransmitter that leads to depolarization of skeletal muscle by increasing the concentration of sodium ion channels. The parasympathetic nervous system releases Acetylcholine neurotransmitter that acts on the cardiac muscle.

Detailed explanation-3: -Acetylcholine is the chief neurotransmitter of the parasympathetic nervous system, the part of the autonomic nervous system (a branch of the peripheral nervous system) that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.