Anatomy and Physiology II Practice Test 2025 - Free Anatomy Practice Questions and Study Guide

Blood pressure is influenced by a variety of physiological factors, of which blood volume and heart rate are two critical components.

Blood volume refers to the total amount of blood in the circulatory system. An increase in blood volume typically raises blood pressure, as there is more fluid being pushed through the blood vessels. Conversely, a decrease in blood volume can lower blood pressure.

Heart rate, which is the number of times the heart beats per minute, also plays a significant role. An increase in heart rate elevates the amount of blood pumped into the arteries, which can contribute to an increase in blood pressure.

Together, blood volume and heart rate effectively regulate both the cardiac output—the amount of blood the heart pumps—and the pressure exerted on the arterial walls, making them essential factors in determining blood pressure levels.

In contrast, while blood viscosity and peripheral resistance (mentioned in the other option) do influence blood pressure, the context of this question points to the more direct regulatory factors of volume and heart rate as broader determinants.