Which of the following affect blood pressure? (1) Diameter of blood vessels, (2) Systolic pressure of the ventricle, (3) Return of blood to the heart.

Correct answer: 1, 2 and 3. Blood pressure depends on how narrow the vessels are, how strongly the ventricle pumps, and how much blood returns to the heart.

Background: Narrow vessels raise blood pressure, and wider vessels lower it.

• 1 only: Vessel diameter is only one of the factors.
• 3 only: Venous return is only one of the factors.
• 2, 3 only: Ventricle pressure and venous return are important, but vessel diameter also matters.

Did you know? Blood pressure is measured with a sphygmomanometer.

Memory trick: Vessels + pump + return = all three.