The calcium that triggers muscle contraction is stored in
A)the motor neuron.
B)synaptic vesicles.
C)the endoplasmic reticulum.
D)the mitochondria.

Question

Quizplus · Accepted Answer

The calcium that triggers muscle contraction is stored in the endoplasmic reticulum of muscle cells. When a muscle fiber receives a signal to contract from a motor neuron, that signal is passed along the muscle fiber's plasma membrane and into the sarcoplasmic reticulum (a specialized type of endoplasmic reticulum). The SR releases calcium ions into the cytoplasm of the muscle fiber, which initiates a series of biochemical events that ultimately lead to muscle contraction.

The Calcium That Triggers Muscle Contraction Is Stored in