Which of the following electrolytes plays a crucial role in the regulation of muscle contraction and relaxation by acting as a cofactor for the enzyme ATPase?

A Sodium
B Potassium
C Calcium
D Magnesium ✓

Explanation

Magnesium acts as a cofactor for the enzyme ATPase, which plays a crucial role in the regulation of muscle contraction and relaxation. Magnesium deficiency can lead to muscle weakness, cramps, and fatigue.

Mnemonic

Mag = Muscle → magnesium for muscle function

Source

Berne and Levy Physiology
Electrolytes and Acid-Base Balance Physiology Electrolyte Functions Hard MEDICAL Confidence: high