What makes up contractility
Contractility tells us how many myosin heads are working at the end of systole; a number that goes up or down with the level of sympathetic nerve stimulation. Rishi is a pediatric infectious Contractility is the intrinsic strength of the cardiac muscle independent of preload, but a change in preload will affect the force of contraction. Afterload is the ‘load’ to which the heart must pump against. Afterload goes down when aortic pressure and systemic vascular resistance decreases through vasodilation. Contractility: The inherent vigor of contraction of the heart muscles during systole. Afterload: The pressure against which the heart must work to eject blood during systole. Starling's Law is the relationship between preload and stroke volume .