Stretching Cardiac Muscle Results in an Increase in the Force

Question

Stretching cardiac muscle results in an increase in the force of contraction as a result of: A)Activation of K⁺ channels. B)An increase in the sensitivity of actin-myosin interactions to Ca⁺⁺. C)Phosphorylation of the ryanodine receptor. D)Increased phosphorylation of troponin I. E)Increased Ca⁺⁺ influx through the Na⁺-Ca⁺⁺ antiporter.

Accepted Answer

Stretching cardiac muscle leads to an increase in the sensitivity of actin-myosin interactions to Ca⁺⁺, leading to an increase in the force of contraction. This is known as the Frank-Starling mechanism. The other options listed do not directly explain this phenomenon.