MUSCLE PHYSIOLOGY

Detailed explanation-1: -Without T-tubules, the muscle could not be signaled by the brain to contract, as T-tubules help signal within the cell to contract. T-tubules activate release of calcium from the sarcoplasmic reticulum, which allows for the contraction of muscle fibers by unblocking the F-actin binding site on myosin.

Detailed explanation-2: -Abstract. The transverse tubules (T-tubules) of mammalian cardiac and skeletal muscles are invaginations of the sarcolemma. They play a crucial role in excitation-contraction coupling as well as in intracellular signaling and in regulation of glucose transport.