Definition
- Excitation-contraction coupling (ECC) is the process pairing the electrical event, sarcolemmal and T-tubule depolarization, with the mechanical event, cross-bridge cycling, in skeletal muscle.
- It spans the latent period, about 2 ms between the action potential's onset and the start of the twitch's contractile response.
Sarcotubular System
- The T-tubule (dihydropyridine, DHP, receptor, a voltage sensor) and the terminal cisternae of the SR (ryanodine receptor, a Ca2+ release channel) together form a triad, the coupling apparatus.
Sarcotubular system, relationship of T-tubules and sarcoplasmic reticulum to the sarcomere