Answer
Acetylcholine (ACH) is contained in the synaptic vesicles of the synaptic knob at the end of a terminal branch of a somatic motor neuron. When the action potential (AP) reaches the synaptic knob , it cannot cross the synaptic cleft. Instead, it stimulates the release of acetylcholine (ACH) from synaptic vesicles and the ACH pours into the the synaptic cleft.
Work Step by Step
ACH stimulates the muscle fiber by binding to acetylcholine receptors (ACHRs) in the sarcolemma of the motor end plate. This ligand (ACH) stimulates the muscle fiber and generates an end plate potential. If the end plate potential is adequate to generate an action potential, the muscle cell will contract.
After the ACH has stimulated the myofiber to contract, its activity is ended by the release of the enzyme acetylcholinesterase (ACHe). ACHe is secreted by the basal lamina and the sarcolemma; it breaks down ACH.
ends the neurotransmitter action, and enables the muscle fiber to relax. Fragments of ACH ( AcetylcoA and choline) are reabsorbed for by the synaptic knobs for reuse.
