Which structure is an extension of the sarcolemma or cell membrane,which penetrates the interior of the muscle and carries the electrical signal to the deepest part of the muscle?
A)Sarcoplasmic reticulum
B)T tubule
C)Z line
D)Tendon

Question

Quizplus · Accepted Answer

T-tubules are extensions of the muscle cell membrane that penetrate deep into the muscle fibers. They are responsible for carrying the electrical impulses (action potentials) that trigger muscle contraction from the surface of the muscle to the innermost regions of the muscle fibers. The sarcoplasmic reticulum, on the other hand, is a network of tubules and sacs within the muscle fiber that stores and releases calcium ions, which are necessary for muscle contraction. The Z-line is a protein structure within the muscle fiber that anchors the thin filaments of the muscle fibers, and tendons are tough bands of connective tissue that attach muscle to bone.

Which Structure Is an Extension of the Sarcolemma or Cell