Epinephrine Increases the Force of Contraction of Cardiac Muscle By

Question

Epinephrine increases the force of contraction of cardiac muscle by: A)Increasing the amount of Ca⁺⁺ in the SR for release to the cytosol. B)Increasing the level of myosin light-chain phosphorylation. C)Inhibiting the ryanodine receptor. D)Increasing Ca⁺⁺ extrusion through the sarcolemmal Ca⁺⁺ pump. E)Shortening the duration of the action potential.

Accepted Answer

Epinephrine increases the force of contraction of cardiac muscle primarily by increasing the amount of calcium in the sarcoplasmic reticulum (SR) for release to the cytosol, which enhances the contractility of the heart muscle.