Excitation-contraction coupling begins with

A) the depolarization at the T tubules.
B) the production of an action potential in the sarcolemma.
C) the release of Ca²⁺ from the sarcoplasmic reticulum.
D) the release of the cross-bridge.

Excitation-Contraction Coupling

The physiological process that links muscle fiber excitation to muscle contraction, primarily in skeletal and cardiac muscles.

T Tubules

Extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells, aiding in the transmission of electrical impulses.

Action Potential

A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane.