Frank–Starling

Frank-Starling Law

The Frank-Starling law, also known as the Frank-Starling mechanism or Starling's law, is a principle that describes how the heart's stroke volume changes in response to changes in venous return. It is named after two physiologists, Ernest Starling and Otto Frank, who made significant contributions to the understanding of heart function.

Overview[edit | edit source]

The Frank-Starling law states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (the end diastolic volume) when all other factors remain constant. The increased volume of blood stretches the ventricular wall, causing cardiac muscle to contract more forcefully (the so-called preload). The increased contractility results in an increased volume of blood ejected (Stroke Volume).

Mechanism[edit | edit source]

The mechanism behind the Frank-Starling law involves the length-tension relationship in cardiac muscle. As the cardiac muscle is stretched by increased blood volume, the actin and myosin filaments within the muscle cells overlap to a greater degree. This increased overlap allows for a greater degree of interaction between the filaments, which in turn leads to a stronger contraction and thus a greater stroke volume.

Clinical significance[edit | edit source]

The Frank-Starling law has important implications in clinical medicine. It explains why, in heart failure, the heart is unable to pump out as much blood as it receives. It also provides the basis for the use of drugs that increase venous return (preload) in the treatment of heart failure.