Which term describes the opposition to blood flow through arteries, increasing pressure when vessels are constricted?

• A. Cardiac output
• B. Mean arterial pressure
• C. Peripheral vascular resistance
• D. Heart rate

Answer: (C)

The main idea here is the opposition to blood flow created by the arteries themselves. When vessels constrict, the resistance to flow increases, and more pressure is needed to push the same amount of blood through the systemic circulation. The term that captures this opposition is peripheral vascular resistance. It reflects how the tone and radius of systemic arterioles contribute to resistance; because resistance rises especially as arterioles narrow, arterial pressure tends to increase if flow remains constant, which aligns with the basic relationship ΔP = Q × R (and the idea that smaller radius greatly raises resistance). Mean arterial pressure, while related, is the pressure result that depends on both flow (cardiac output) and resistance, not the resistance itself. Cardiac output describes how much blood the heart pumps per minute, and heart rate is how fast the heart beats—neither describes the resistance offered by the arteries.