What happened to the pump rate when the stroke volume increased, according to the material?

What happened to the pump rate when the stroke volume increased, according to the material?

• A. The pump rate decreased to maintain cardiac output
• B. The pump rate remained unchanged
• C. The pump rate increased to maintain cardiac output
• D. The pump rate first increased then decreased

Answer: (C)

Cardiac output is the product of how much blood the heart pumps with each beat (stroke volume) and how many beats occur each minute (pump rate). When stroke volume increases, the heart often responds by beating faster as well, driven by sympathetic activation that increases contractility and rate. This combination raises the overall blood flow to meet higher metabolic demands, so the pump rate increases to maintain (or increase) cardiac output in the situation described. In other words, more blood per beat is delivered, and pumping more times per minute helps deliver even more total blood flow to tissues.

Cardiac output is the product of how much blood the heart pumps with each beat (stroke volume) and how many beats occur each minute (pump rate). When stroke volume increases, the heart often responds by beating faster as well, driven by sympathetic activation that increases contractility and rate. This combination raises the overall blood flow to meet higher metabolic demands, so the pump rate increases to maintain (or increase) cardiac output in the situation described. In other words, more blood per beat is delivered, and pumping more times per minute helps deliver even more total blood flow to tissues.