Define cardiac output and stroke volume
Answers
Cardiac output:The amount of blood the heart pumps through the circulatory system in a minute. The amount of blood put out by the left ventricle of the heart in one contraction is called the stroke volume. The stroke volume and the heart rate determine the cardiac output. A normal adult has a cardiac output of 4.7 liters (5 quarts) of blood per minute.
Stroke volume: The amount of blood pumped by the left ventricle of the heart in one contraction. The stroke volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat. Together with the heart rate, the stroke volume determines the output of blood by the heart per minute (cardiac output).
During cardiac cycle, each ventricle pumps out approximately 70 ml of blood which is called stroke volume.
Stroke volume multiplied by heart rate (70 ml × 72 ≈ 5 liters) gives cardiac output. Thus, cardiac output is the volume of blood pumped out by each ventricle per minute.
A healthy individual has about 5 liters of blood. Thus, entire blood is circulated throughout the body within one minute.