Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to
A) the nucleus.
B) the sarcolemma.
C) the endomysium.
D) the sarcoplasmic reticulum.
E) thick filaments.

Question

Quizplus · Accepted Answer

T-tubules form triads with the sarcoplasmic reticulum, and at these junctures, the T-tubule is tightly bound to the sarcoplasmic reticulum. This allows for efficient communication between the action potential in the T-tubule and the release of calcium ions from the sarcoplasmic reticulum, which is necessary for muscle contraction.

Regarding a Skeletal Muscle Fiber, Wherever a T-Tubule Encircles a Myofibril