18. The Heart

When the pressure inside the ventricle causes the atrioventricular valve to close and the semilunar valve to open, which statement about the heart is true?

For the atrioventricular valves to be open, the pressure in the ventricles must be:

What event immediately follows the closure of the atrioventricular valves and coincides with the onset of ventricular systole?

During which following phase (or phases) of the cardiac cycle is the blood volume in the ventricles constant?

During diastole, a chamber of the heart:

(a) Relaxes and fills with blood

(b) Contracts and pushes blood into an adjacent chamber

(c) Experiences a sharp increase in pressure

(d) Reaches a pressure of approximately 120 mm Hg

During the cardiac cycle, the amount of blood ejected from the left ventricle when the semilunar valve opens is the:

(a) Stroke volume (SV)

(b) End-diastolic volume (EDV)

(c) End-systolic volume (ESV)

(d) Cardiac output (CO)

Define cardiac cycle, and follow the events of one cycle.

What is cardiac output, and how is it calculated?