FrankStarlingprincipen

The Frank-Starling mechanism, also known as the Starling mechanism or the Frank-Starling law of the heart, is a fundamental principle in cardiovascular physiology that describes the relationship between the volume of blood filling the heart and the force with which it contracts. Essentially, it states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction. This occurs because greater filling of the ventricles, known as increased preload, stretches the cardiac muscle fibers. When these fibers are stretched to an optimal point, they contract more forcefully, ejecting a larger volume of blood.

This mechanism is crucial for maintaining adequate blood flow to the body. During periods of increased venous return, such as after exercise or when lying down, the heart automatically adjusts by filling more and contracting more strongly, ensuring that all the returning blood is pumped out. Conversely, when venous return is low, the heart will fill less and contract with less force. The Frank-Starling mechanism operates largely independently of external neural or hormonal influences, acting as an intrinsic property of the heart muscle itself. It plays a vital role in matching cardiac output to the body's metabolic demands under varying physiological conditions.