What structures carry the action potentials into the interior of the muscle to cause muscle contraction?
A)T tubules
B)terminal cisternae
C)sarcoplasmic reticula
D)ryanodine receptors

Question

Quizplus · Accepted Answer

T tubules are invaginations of the sarcolemma that penetrate deep into the muscle fiber. Action potentials traveling along the sarcolemma rapidly spread into the T tubules, which then carry the action potentials into the interior of the muscle fiber. This triggers the release of calcium ions from the sarcoplasmic reticulum, which ultimately leads to muscle contraction. Terminal cisternae and sarcoplasmic reticula are involved in the release of calcium ions, but they do not directly carry the action potentials. Ryanodine receptors are calcium release channels located on the sarcoplasmic reticulum.

What Structures Carry the Action Potentials into the Interior of the Muscle