What connects the components of a triad?

The correct answer is that proteins that control calcium release connect the components of a triad. In muscle physiology, a triad is a critical structure found at the junction of the sarcoplasmic reticulum and the transverse (T) tubules in skeletal muscle fibers. It comprises two terminal cisternae of the sarcoplasmic reticulum and one T-tubule.

Central to the function of the triad is the release of calcium ions, which is essential for muscle contraction. The proteins responsible for this, such as the ryanodine receptors located on the terminal cisternae, interact with the voltage-sensitive dihydropyridine receptors found in the T-tubules. When an action potential travels along the T-tubule membrane, it triggers these proteins to release calcium from the sarcoplasmic reticulum into the cytoplasm, leading to contraction.

The other options, although significant in the context of muscle structure and function, do not define how the triad components are connected directly. Myofilaments play a vital role in muscle contraction but are not part of the structural connection of the triad itself. Muscle fibers describe the overall structure of the muscle but do not specifically relate to the triad system as their connection