Which of the following is NOT described as a typical response to low blood pressure?

• A. Cardiac output will increase
• B. Vasoconstriction occurs
• C. Heart rate increases
• D. Renal perfusion decreases

Answer: (A)

When blood pressure falls, the body activates quick reflexes to restore it. The baroreceptor reflex boosts sympathetic activity, which causes blood vessels to constrict and the heart to beat faster. The kidneys also feel the lower pressure, so renal perfusion drops and the body can trigger hormonal systems to help raise BP. In this situation, cardiac output does not reliably rise—speeding up the heart can be offset by less filling of the heart, so stroke volume may decrease and overall output can stay the same or drop. That’s why saying cardiac output will increase isn’t a typical description of the response to low blood pressure. The expected responses include vasoconstriction, an increased heart rate, and decreased renal perfusion as part of the body’s attempt to restore pressure.