Question

Which blood vessels have the lowest blood pressure?

Answer 1

In the general circulation, the highest blood pressure is found in the aorta and the lowest blood pressure is in the vena cava. As this suggests, blood pressure drops in the general circulation as it goes from the aorta to the rest of the body.

Answer 2

Veins, especially venules, have the lowest blood pressure within the circulatory system because of the significant drop in pressure after blood has passed through the arterioles and capillaries.

Step-by-step explanation:

The blood vessels that have the lowest blood pressure are the veins, specifically as blood approaches and enters the venules and continues through the venous system. While blood is initially pumped from the heart into the arteries at high pressure, by the time it has passed through the capillaries and entered the venules, the pressure has markedly decreased. This decrease in pressure is due to the friction of blood against vessel walls as arteries subdivide into smaller arterioles and further into capillaries, creating more resistance.

Additionally, veins and venules have wider lumens and thinner walls compared to arteries, which combined with the low resistance, allow blood to flow back to the heart at a lower pressure. Many veins, especially in the limbs, possess valves that facilitate the flow of blood toward the heart amidst this reduced pressure and the pull of gravity.