Neuromuscular Junction: How Nerves Trigger Muscle Contraction #2267178 (License: Personal Use)

This scientific illustration depicts the neuromuscular junction, where a motor neuron terminal releases acetylcholine into the synaptic cleft, binding to receptors on the muscle fiber membrane. This triggers voltage-gated calcium channels to open, allowing Ca²⁺ influx that initiates actin-myosin cross-bridge cycling and sarcomere shortening. The inset highlights the striated structure of the muscle fiber with visible Z-lines and the central nucleus.

Used in physiology, anatomy, or neuroscience educational content-especially for explaining excitation-contraction coupling. Matches user intent for learning how voluntary movement is initiated at the cellular level.