Excitation-Contraction Coupling

These flashcards cover the key vocabulary and concepts related to the mechanisms of muscle contraction through excitation-contraction coupling.

Excitation-Contraction Coupling (E-C Coupling)

The physiological process in which an electrical impulse triggers calcium release, leading to muscle contraction.

Calcium channels

Voltage-sensitive channels in the terminal cisterna that, when opened, allow calcium to flow into the cytosol.

TnC

Troponin C, a protein that binds calcium and initiates a conformational change in the troponin complex.

Cross-bridge formation

The attachment of myosin heads to actin binding sites, forming a transient complex that leads to muscle contraction.

Power stroke

The action when the myosin head pivots and pulls the actin filament toward the M line, releasing ADP and P.

Troponin

A protein complex that, when bound by calcium, changes shape and moves tropomyosin away from myosin binding sites on actin.

Myosin-binding sites

Specific sites on actin filaments that become exposed when troponin is activated by calcium, allowing for muscle contraction.

H-Zone

The region of the sarcomere that represents the area where only thick filaments (myosin) are present and is reduced during contraction.