Physiology Quiz -
Cardiac Cycle - Part 3
The cardiac cycle refers to the sequence of events that takes place from one heart beat to the next. A full understanding of the cardiac cycle requires thorough examination of atrial systole, atrial diastole, ventricular systole, ventricular diastole, atrial and ventricular volume changes during the cycle, electrical events (depolarization and repolarization) of atria and ventricular myocytes, heart sounds associated with turbulent blood flow caused by the closure of semilunar valves, as well as hydrostatic blood pressure changes within the atria, ventricles, and the aorta. Test you basic understanding of the cardiac cycle by taking this simple quiz.
(1)   During the cardiac cycle, the relaxation phase is referred to as __________.

(2)   During the isovolumic contraction (also referred to as isovolumetric contraction) phase of the cardiac cycle:
 (A)   The hydrostatic pressure in the left ventricle is higher than the hydrostatic pressure in the left atrium. (B)   The hydrostatic pressure in the left ventricle is lower than the hydrostatic pressure in the left atrium. (C)   The hydrostatic pressure in the left ventricle is higher than the hydrostatic pressure in the aorta. (D)   The hydrostatic pressure in the left ventricle is lower than the hydrostatic pressure in the aorta.
(3)   During the isovolumic relaxation (also referred to as isovolumetric relaxation) phase of the cardiac cycle:
 (A)   The hydrostatic pressure in the left ventricle is higher than the hydrostatic pressure in the left atrium. (B)   The hydrostatic pressure in the left ventricle is lower than the hydrostatic pressure in the left atrium. (C)   The hydrostatic pressure in the left ventricle is higher than the hydrostatic pressure in the aorta. (D)   The hydrostatic pressure in the left ventricle is lower than the hydrostatic pressure in the aorta.
(4)   If the heart rate is 70 beats per minute, what is the total duration (in milliseconds, ms) of any individual cardiac cycle?
 (A)   429 ms (B)   583 ms (C)   857 ms (D)   1167 ms (E)   1714 ms
(5)   When the heart rate increases, the duration of each cardiac cycle __________.
 (A)   increases (B)   decreases

Posted: Tuesday, March 22, 2016