تسجيل الدخول

تسجيل

Neuromuscular Junction

المؤلف:  Kim E. Barrett, Susan M. Barman, Heddwen L. Brooks, Jason X.-J. Yuan

المصدر:  Ganongs Review of Medical Physiology

الجزء والصفحة:  25th E, P130

2026-09-24

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Figure 1 shows the components of the neuromuscular junction. As the axon supplying a skeletal muscle fiber approaches its termination, it loses its myelin sheath and divides into a number of terminal boutons (Figure 1). The terminal contains many small, clear vesicles that contain acetylcholine, the transmitter at these junctions. The endings fit into junctional folds, which are depressions in the motor endplate, the thickened portion of the muscle membrane at the junction. The space between the nerve and the thickened muscle membrane is comparable to the synaptic cleft at neuron-to-neuron synapses. The whole structure is known as the neuromuscular junction. Only one nerve fiber ends on each endplate, with no convergence of multiple inputs.

Fig1. The neuromuscular junction. A) Scanning electron micrograph showing branching of motor axons with terminals embedded in grooves in the muscle fiber’s surface. B) Structure of a neuromuscular junction. (Modified with permission from Widmaier EP, Raff H, Strang KT: Vanders Human Physiology. New York, NY: McGraw-Hill; 2008.)