Physician Assistant College Admission Test (PA-CAT) Entrance Practice exam

Cardiac output is defined as the volume of blood that the heart pumps out into the circulation each minute. This measurement is crucial in understanding how effectively the heart is functioning to supply blood to meet the body’s demands for oxygen and nutrients. Cardiac output is typically calculated by multiplying heart rate (the number of beats per minute) by stroke volume (the amount of blood ejected from the heart with each beat). This reflects the heart's overall performance and plays a central role in cardiovascular physiology.

The other choices provided describe different aspects of the cardiovascular system. The volume of blood returned to the heart by the veins is known as venous return, which is important for determining stroke volume but is not the same as cardiac output. The total volume of blood in the body refers to blood volume, which is a separate measurement from cardiac output. Blood pressure in the arteries reflects the force exerted by circulating blood on the walls of blood vessels, which is measured in millimeters of mercury (mmHg) and is also distinct from cardiac output.