Ex. 3 Mechanical properties of the heart

Question 1

What is preload?

Answer 1

the amount of tension (stretch) in the ventricular myocardium, precontraction.

Question 2

If you increase preload you also increase what?

Answer 2

stroke volume

Question 3

What is afterload?

Answer 3

the pressure the ventricle must pump against

Question 4

What are indices of cardiac preload?

Answer 4

1. end diastolic volume (EDV) or pressure of ventricle
2. Right ventricular pressure or left ventricular pressure
3. Central venous pressure (entire heart)

Question 5

What are the indices of cardiac afterload?

Answer 5

1. aortic pressure to left ventricle
2. pulmonary arterial pressure to right ventricle
3. increases in afterload can decrease stroke volume

Question 6

What is Frank Starling Law of the Heart?

Answer 6

Length tension relationship. As stroke volume increases in response to an increase in the volume of blood filling the heart when all other factors remain constant