Question

Which of the following statements best describes mean arterial pressure (MAP)?

A. It represents the amount of end diastolic volume that is ejected from the heart by contraction of the left ventricle.
B. It represents the force exerted by the blood on the walls of blood vessels during the contraction of the ventricles.
C. It represents the resistance against which the ventricles must contract in order to eject blood into systemic circulation.
D. It represents the depolarization of the AV node that is carried into the ventricles by the atrioventricular bundle.
E. It represents the volume of blood ejected with each contraction of the left ventricle.

Answer 1

Mean arterial pressure (MAP) describes the average pressure in the arteries, calculated as the diastolic blood pressure plus one-third of the pulse pressure, indicating the average force propelling blood into the tissues.

Step-by-step explanation:

The statement that best describes mean arterial pressure (MAP) is that it represents the "average" pressure of blood in the arteries over time, giving an indication of the average force driving blood into vessels that serve the tissues. MAP can be approximated using the formula MAP = diastolic BP + (pulse pressure/3), where pulse pressure is the difference between systolic and diastolic pressures (systolic BP - diastolic BP). MAP reflects the balance between cardiac output and systemic vascular resistance, with systemic blood pressure being influenced by factors such as cardiac output, compliance, blood volume, blood viscosity, and blood vessel diameter.

Blood pressure is measured as a ratio of systolic over diastolic pressure. Systolic pressure occurs during ventricular contraction (systole), while diastolic pressure is the pressure in the arteries when the ventricles are at rest (diastole). MAP is related to but distinct from these measures as it accounts for the fact that the heart spends more time in diastole than systole.