(SG14) What did Starling find and how does it relate to Starling's law of the heart?
English physiologists Ernest Starling, expanding earlier work of Otto Frank (Frank-Starling), found that, within limits, i.e. normal conditions, the longer or more stretched myocardial fibers are at the beginning of a contraction, the stronger that contraction will be.
What influences how stretched these muscle fibers get is directly related to how much venous blood is returned to the ventricles, or venous return. The effect is that under normal conditions, the heart will pump out the amount of blood that is returned to it.