A triad is composed of a t-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected?

Calcium release

Explanation:

These components are connected by a series of proteins that control calcium release

Invaginations of the plasma membrane (sarcolemma) of the muscle fibres are called T or transverse tubules The two terminal cisternae of the sarcoplasmic reticulum (SR) together with their associated T tubule are known as a triad Inside the muscle fiber, the T-tubules lie next to the terminal cisternae of an internal membrane system derived from the endoplasmic reticulum, called the sarcoplasmic reticulum (SR) which is a store of calcium ions Stimulation of the muscle fiber, causes a wave of depolarization to pass down the t-tubule, and the SR to release calcium ions into the sarcoplasm Calcium is pumped back up into the SR to lower calcium ion concentration in the sarcoplasm, to relax the muscle (turn off contraction)