Question

The Frank Starling law of the heart states:

	a) The ventricles will expand and allow greater blood to enter during diastole
	b) The amount of stretch of the muscle will decrease the ejection fraction
	c) The myocardium will stretch with an increased afterload by reducing ejection fraction
	d) The greater stretch of the muscle the larger the contraction will be

Answer 1

The Frank–Starling law of the heart states

A) the heart will expand and hence greater volume of blood enters during the diastole

B) The amount of stretch of the muscle will increase and not decrease the ejection fraction

C) The dialated myocardium will reduce ejection fraction

D) The greater strech of the muscle this will inturn increase the force of contraction of heart muscles

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. In other words, as a larger volume of blood flows into the ventricle, the blood will stretch the walls of the heart, causing a greater expansion during diastole, which in turn increases the force of the contraction and thus the quantity of blood that is pumped into the aorta during systole. The increased volume of blood stretches the ventricular wall, causing cardiac muscle to contract more forcefully (the so-called Frank–Starling mechanisms). The stroke volume may also increase as a result of greater contractility of the cardiac muscle during exercise, independent of the end-diastolic volume. The Frank–Starling mechanism appears to make its greatest contribution to increasing stroke volume at lower work rates, and contractility has its greatest influence at higher work rates.

This allows the cardiac output to be synchronized with the venous return, arterial blood supply and