Starling's Law describes which relationship?

• A. Afterload Determines The Force Of Contraction
• B. Preload Has No Effect On Contraction
• C. Contractility Increases Independently Of Stretch
• D. The Greater Preload, The Force Of Contraction

Answer: (D)

Starling's law describes how the heart's force of contraction increases with greater preload. When more blood returns to the ventricle, the ventricular fibers are stretched to a longer length, which enhances the overlap of contractile filaments and produces a stronger contraction, increasing stroke volume up to the heart’s length-tension limit. This concept explains how the amount of venous return directly influences the force of ejection. It’s not about afterload, and it’s not about contraction being independent of stretch; the length-tension relationship of cardiac muscle governs this effect.