Answer:
The nervous system is very important for physical activity since it regulates motor activity through alpha motor neurons, or through innervations in smooth and skeletal muscle.
The alpha motor neuron, is a neuron that is responsible for inventing the skeletal muscles that coordinate locomotion, the presynaptic membrane of the motor neuron, plus the intersynaptic space, and the postsynaptic membrane form the motor unit.
The motor unit is in charge of generating the action potential necessary for the muscle fibers to contract, the z lines and myosin approaching with actin.
skeletal muscle contraction in turn is assimilated by different areas, that is why some movements are involuntary, other reflex arches and others are movements acquired or constantly practiced.
The movements of locomotion are so repetitive and since they are also the first learned, they are considered reflex arcs because they are involuntary, the human being does not send the intentional voluntary signal to execute them.
In turn, each movement, the more meticulous it is, the more it will have to be rehearsed or practiced, in order to develop what some people call "fine motor skills".
All this is a consequence that the CNS and the SNP are the guides and activators of muscle movements.
Explanation:
When an electrical impulse or action potential passes through the axon of a motor neuron, upon reaching the terminal or synaptic button, a depolarization wave will be produced that will stimulate the calcium ions found in the cleft or synaptic space to adhere to the presynaptic membrane. or even some enter the synaptic button and cause the synaptic vesicles to approach the presynaptic membrane. In one way or another, the vesicles approach the membrane, fuse with it, and, by exocytosis, release the neurotransmitter into the synaptic space.
The most frequent neurotransmitter in this type of synapse is acetylcholine, which has its receptors on the postsynaptic membrane. By flooding the synaptic space and occupying the receptors, a stimulus is activated that causes the channels for the sodium ion to open and depolarization begins in the postsynaptic membrane. Acetylcholine cannot be in constant action, so an enzyme called acetylcholinesterase is released causing the disconnection between the neurotransmitter and the receptor, resulting in the neurotransmitter in the synaptic space dividing into 2 parts: 1 part of acetyl and another portion of choline. Once the portions are separated, they can be reabsorbed with the synaptic button or simply finish degrading in the synaptic space.
