According to the Frank-Starling Law, what happens as the myocardial fibers are stretched?

The Frank-Starling Law describes the relationship between the stretch of myocardial fibers and the force of heart contractions. According to this principle, as the myocardial fibers in the heart are stretched—typically due to an increase in venous return or blood volume—the heart's ability to contract forcefully also increases. This is because the stretching of the fibers optimally aligns the actin and myosin filaments within the cardiac muscle cells, leading to more effective contractions.

Stronger cardiac contractions occur as an adaptive mechanism, enabling the heart to pump more blood in response to greater volumes. This law is fundamental in understanding how the heart responds to varying levels of blood return and is critical in the management of heart failure, where the efficiency of these contractions can be compromised. The mechanism effectively enhances cardiac output, providing the body with the necessary blood flow according to physiological demands. This is why the chosen answer aligns with the principles of cardiac physiology established by the Frank-Starling Law.