A neuromuscular junctionis when a synaptic transmission leads to the contraction of the skeletalmuscle. In short, we have the synapse in the middle of a motor neuron andskeletal muscle. The neuromuscular junction is an important factor in the humanbody because it dictates whether we can move and function, if the neuromuscularjunction were to fail us then we would all be in a paralysis state. A simple and easy way of explainingthe Neuromuscular junction is that it involves muscle contraction and in orderfor that to happen it is crucial to know the events of the motor neurons. It allstarts with something called action potential, which is an electrical potentialthat corresponds with the transit of impulse that goes through the membrane of amuscle cell, that then depolarizes the axon terminal, calcium channels or alsoknown as the voltage gate opens, then the calcium ions rush towards theterminal and the vesicles (are like bags filled with calcium) that containscalcium migrate all the way to the end of the terminal. Next the vesicles startto fuse with the plasma membrane of the terminal and acetylcholine goes freelytowards the synaptic cleft. Acetylcholine receptors that are at the end of the motorplate attach to acetylcholine which then the sodium channels open, know as aligand-gated, which causes a dash of sodium ions to go directly into thesarcoplasm.
The action potential is then constructed into the sarcolemma andthe action potential spreads throughout it. Action potential then journeys downthrough the transverse tubule, which is a deep well that is ran into the interiorof a fiber. This causes a somewhat trigger in the sarcoplasmic reticulum so itcan free calcium ions into the sarcoplasm.
Then calcium attaches to something calledtroponin and tropomyosin which allows a cross bridge to form. This wholeprocess is what happens when your muscle contracts. This picture below is justsome simple steps of the neuromuscular junction.