Which factor regulates blood pressure by altering cardiac output and peripheral resistance?

Which factor regulates blood pressure by altering cardiac output and peripheral resistance?

• A. Elasticity and muscularity of vessels
• B. Blood glucose level
• C. Oxygen saturation
• D. Kidney filtration rate

Answer: (A)

Regulating blood pressure relies on two main players: how much blood the heart pumps (cardiac output) and how much resistance the vessels offer (peripheral resistance). The elasticity and muscularity of the vessels are the key factors here because they determine vessel diameter and wall stiffness. The smooth muscle in the arterioles can constrict to raise resistance, or relax to lower it, causing rapid changes in blood pressure. Arterial elasticity also shapes pulse pressure; stiffer arteries transmit higher systolic pressures and influence overall mean pressure. In short, vessel tone and wall properties directly modulate peripheral resistance and, together with cardiac output, set blood pressure. Other options don’t regulate BP by changing CO and resistance in the moment: blood glucose level affects long-term vascular health rather than immediate pressure control; oxygen saturation relates to oxygen carrying capacity, not immediate pressure regulation; kidney filtration rate affects fluid balance and BP chronically, not the acute adjustment via vessel diameter and cardiac output.

Regulating blood pressure relies on two main players: how much blood the heart pumps (cardiac output) and how much resistance the vessels offer (peripheral resistance). The elasticity and muscularity of the vessels are the key factors here because they determine vessel diameter and wall stiffness. The smooth muscle in the arterioles can constrict to raise resistance, or relax to lower it, causing rapid changes in blood pressure. Arterial elasticity also shapes pulse pressure; stiffer arteries transmit higher systolic pressures and influence overall mean pressure. In short, vessel tone and wall properties directly modulate peripheral resistance and, together with cardiac output, set blood pressure.

Other options don’t regulate BP by changing CO and resistance in the moment: blood glucose level affects long-term vascular health rather than immediate pressure control; oxygen saturation relates to oxygen carrying capacity, not immediate pressure regulation; kidney filtration rate affects fluid balance and BP chronically, not the acute adjustment via vessel diameter and cardiac output.