The calcium that triggers muscle contraction is stored in the
A) motor neuron.
B) plasma membrane of cells.
C) endoplasmic reticulum.
D) mitochondria.

Question

Quizplus · Accepted Answer

The calcium ions that trigger muscle contraction are stored in the sarcoplasmic reticulum, a type of endoplasmic reticulum found in muscle cells. When an action potential (nerve impulse) reaches the muscle cell, it triggers the release of calcium ions from the sarcoplasmic reticulum, which then bind to specific proteins (troponin and tropomyosin) in the muscle fibers, leading to muscle contraction.

The Calcium That Triggers Muscle Contraction Is Stored in the