Determinants of Blood Pressure

Steps:

• Blood pressure (BP) is determined by cardiac output (CO) × total peripheral resistance (TPR).
• Factor 1: Smaller vessel diameter increases TPR via Poiseuille's law, raising BP.
• Factor 2: Higher systolic ventricular pressure increases arterial systolic pressure and CO.
• Factor 3: Greater venous return boosts preload, stroke volume, and CO per Frank-Starling mechanism.

Why A is correct:

• BP formula (BP = CO × TPR) shows all three factors directly influence either CO or TPR.

Why the others are wrong:

• B: Excludes factor 2, but ventricular systolic pressure drives arterial pressure.
• C: Ignores factors 2 and 3, which affect CO.
• D: Omits factor 1, but vessel diameter is key to TPR.

Final answer: A