_____ ions directly control the contraction of muscles.
A) Sodium
B) Potassium
C) Calcium
D) Magnesium

Question

Quizplus · Accepted Answer

Calcium ions directly control the contraction of muscles by binding to the protein complexes actin and myosin, which initiates the sliding of filaments and contraction of the muscle fibers. Sodium and potassium ions are important for generating the action potential necessary for muscle contraction, but do not directly control the contraction process. Magnesium ions play a role in muscle relaxation, but are not directly involved in muscle contraction.

_____ Ions Directly Control the Contraction of Muscles