The sarcolemma

Question

The sarcolemma

Quizplus · Accepted Answer

The sarcolemma is the muscle cell plasma membrane, which encloses the muscle fiber, separating its interior from the external environment. It plays an essential role in controlling the movement of substances into and out of the muscle cell.

Answer: B
 The sarcolemma provides a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fiber, allowing for the coordinated contraction of muscle fibers.

Answer: D
 The sarcolemma runs longitudinally between the myofibrils, which are the contractile structures within muscle fibers that generate force and movement.

Answer: E
 The expanded lateral sacs are part of the sarcoplasmic reticulum, which is responsible for storing and releasing calcium ions during muscle contraction. They are not a characteristic of the sarcolemma.

Answer: C
 The sarcolemma does not store ATP directly, although its membranes may contain enzymes involved in ATP production and utilization. ATP is primarily stored in the mitochondria and myofibrils within the muscle cell.

The Sarcolemma