Questions: What best describes the cardiac output? a. Volume of blood in a vertical column b. Maximum flow velocity within the vessel lumen c. Quantity of blood moving through the vessel per unit of time d. Hydrostatic pressure per minute e. Volume of blood pumped by the heart per minute

The answer is the last one (e): the volume of blood pumped by the heart per minute.

Explanation for each option:

a. Volume of blood in a vertical column: This option is incorrect because it describes a static measurement of blood volume, not a dynamic flow rate.

b. Maximum flow velocity within the vessel lumen: This option is incorrect because it refers to the speed of blood flow at a specific point in the vessel, not the overall volume of blood being pumped by the heart.

c. Quantity of blood moving through the vessel per unit of time: This option is partially correct but is too general. It does not specify that it is the heart's output, which is a crucial aspect of the definition of cardiac output.

d. Hydrostatic pressure per minute: This option is incorrect because hydrostatic pressure refers to the pressure exerted by a fluid at equilibrium due to the force of gravity, not the volume of blood being pumped by the heart.

e. Volume of blood pumped by the heart per minute: This option is correct because cardiac output is defined as the volume of blood the heart pumps in one minute. It is a key measure of heart function and is calculated as the product of stroke volume (the amount of blood pumped with each beat) and heart rate (the number of beats per minute).

Summary: The best description of cardiac output is the volume of blood pumped by the heart per minute.