Which of the Following is Responsible for the Starling Effect

Question

Which of the following is responsible for the Starling effect?
A) Sympathetic nerve firing
B) Vagal discharge
C) Activation of the beta1-adrenergic receptors
D) End-diastolic volume (EDV) or preload

Accepted Answer

The Starling effect is the increase in myocardial contractility that occurs in response to an increase in end-diastolic volume (EDV), or preload. As the amount of blood entering the heart during diastole (EDV) increases, the volume of blood ejected during systole (stroke volume) also increases. This mechanism helps maintain adequate cardiac output during exercise or other situations where the heart needs to work harder. None of the other options listed are responsible for the Starling effect.