My STEAM project is on the neuromuscular autoimmune disorder myasthenia gravis. This relates to the course objective, “Describe how a muscle contraction is induced”. The first image is of a neuromuscular junction of a healthy individual, while the second is of an individual with myasthenia gravis.
An action potential (purple lettering: move) is initiated by a motor neuron and arrives at the axon terminal. Vesicles release acetylcholine (represented by purple dots) into the synaptic gap. Acetylcholine binds to acetylcholine receptors (red lines on the postsynaptic side) on the motor end-plate, beginning the depolarization of the muscle fiber and propagation of the action potential into the muscle.
An action potential is initiated by a motor neuron and arrives at the axon terminal. Vesicles release acetylcholine into the synaptic gap. The junctional folds of the postsynaptic membrane have been simplified by antibodies (Y shaped, and pictured in blue). Antibodies also bind to acetylcholine receptors, blocking acetylcholine from binding with the receptors. Ability for an action potential to consistently enter the muscle fiber is reduced.