endplate, motor

Endplateclick for a larger image
Fig. 148 Endplate . Verticle section of a single synaptic knob (bouton), up to 50 of which terminate the branches of a single neuron and form an endplate.

endplate, motor

the modification of the muscle fibre membrane at a nerve-muscle junction together with the attachment from the DENDRITE (which may consist of up to 50 boutons (SYNAPTIC KNOBS). Only one endplate occurs on each muscle fibre, approximately halfway along, and here the signal transfer from nerve to muscle takes place. ACETYLCHOLINE released from the nerve ending diffuses across this junction and depolarizes the endplate, so giving rise to an endplate potential which, as it builds up, may give rise to an ACTION POTENTIAL and initiate muscle contraction.