Question

The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell?

A)cytosol
B)synaptic cleft
C)within the sarcolemma
D)sarcoplasmic reticulum

Answer 1

Calcium ions, essential for muscle contraction, are stored in the sarcoplasmic reticulum of muscle cells.

Step-by-step explanation:

Calcium ions (Ca2+) play a critical role in muscle contraction and are stored in the sarcoplasmic reticulum (SR) of muscle cells. When an action potential reaches the muscle fiber, it travels along the sarcolemma and into the transverse tubules (T-tubules). The change in voltage opens the Ca2+ channels in the SR, resulting in the release of Ca2+ into the sarcoplasm. These calcium ions enable the interaction between actin and myosin filaments, leading to muscle contraction.