Question

Describe the components of the neuromuscular junction and how an action potential crosses it

Answer 1

ANSWER :

The neuromuscular junction is a specific connection (gap junction) between the motor neurons (axon terminals) and sarcolemma (cell membrane) of skeletal muscle fibres to transmit the action potential or electrical impulse in muscle fibres, required to stimulate their contractions. When an action potential reached at the end of axon (terminals) of a motor neuron, it stimulates flow of Ca++ followed by release of acetylcholine neurotransmitter from the synaptic vesicles into the synaptic cleft, which crosses the gap junction and bind to nicotinic receptors present on the sarcolemma of muscle fibres, and further transmit the electrical signal or action potential in them to contract simultaneously.