In skeletal muscle fibers, what is the source of the calcium ions that are released into the sarcoplasm to bind with troponin, resulting in contraction?
A) Extracellular fluid
B) Sarcoplasmic reticulum
C) Mitochondria
D) Golgi apparatus

Question

Quizplus · Accepted Answer

The sarcoplasmic reticulum (SR) is the source of calcium ions in skeletal muscle fibers. When a muscle fiber is stimulated, the SR releases calcium ions into the sarcoplasm, where they bind to troponin, initiating muscle contraction.

In Skeletal Muscle Fibers, What Is the Source of the Calcium