2D Flashcards
What is the “load” or “stretch” on the ventricular cardiac muscle before it contracts?
Preload
What directly influences preload?
EDV
What is describing the more the ventricles are filled during diastole, the more blood they will eject during systole (i.e. – the greater the preload, the greater the force of contraction)?
Frank-Starling Law of the Heart
What type of regulation describes preload?
Heterometric regulation
What was the analogy of the Frank-Starling Law of the Heart?
A rubber band
What ion is closely related to the Frank-Sterling law?
Calcium! (tropoin affinity and SR)
What concept is INDEPENDENT of Starlings law?
Cardiac Contractility (Inotropism)
What is the factor that throws a wrench into the Frank-Sterliing law?
The SNS! Norepi and Epi
What 2 mechanisms does SNS stimulate via the Beta1 receptors?
1.Increase Ca2+ into cell 2.Increase in Ca2+ into SR
What should be changed to “while”load?
Afterload
What is essentially the BACK PRESSURE exerted on the aortic & pulmonary semilunar valves by arterial blood in the aorta and pulmonary trunk respectively?
Afterload
What does high after load do to SV?
High Afterload = less SV
What does low after load do to SV?
Low afterload= High SV
What are two factors that can increase after load?
Vasoconstriction, increase blood volume, and increased blood viscosity
What types of drugs are often used to decrease after load?
Vasodilators (Nirtoglycerin)
