Which statement concerning the T tubules is correct?

Question

Quizplus · Accepted Answer

T tubules are invaginations of the sarcolemma, which allow the rapid transmission of the action potential from the surface of the muscle fibre to the central portions of the muscle fibre, facilitating synchronous contraction of the myofibrils. Option A is incorrect because Ca2+ ions are stored in the sarcoplasmic reticulum, not in the T tubules. Option C is also incorrect because ATP is produced by the mitochondria, not stored in the T tubules. Option D is partially correct because T tubules do run longitudinally, but they do so perpendicular to the myofibrils, not between them.

Which Statement Concerning the T Tubules Is Correct