ANATOMY

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. Acetylcholine receptors are also found on neurons, where they perform a variety of important functions, including modulating cognition and addiction.

Detailed explanation-2: -When a motor nerve cell gets the proper signal from the nervous system, it releases acetylcholine into its synapses with muscle cells. There, acetylcholine opens receptors on the muscle cells, triggering the process of contraction.

Detailed explanation-3: -Once the action potential reaches the end of the axon terminal, it causes the neurotransmitter acetylcholine (ACh) from synaptic vesicles in the axon terminal. The ACh molecules diffuse across the synaptic cleft and bind to the muscle fiber receptors, thereby initiating a muscle contraction.

Detailed explanation-4: -Acetylcholine, a substance synthesized by neurons, is the primary neurotransmitter of the parasympathetic nervous system, which controls smooth muscle contraction and blood vessel dilation and slows heart rate.

Detailed explanation-5: -Importance of Calcium Ions. Ca2+ ions play an important role in muscle contraction by creating interactions between the proteins, myosin and actin. The Ca2+ ions bind to the C component of the actin filament, which exposes the binding site for the myosin head to bind to in order to stimulate a muscle contraction.