What is the difference between arteries, veins and capillaries?

Arteries, veins, and capillaries are the three types of blood vessels in the human body that play distinct roles in circulating blood throughout the body.

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body’s tissues and organs. Arteries have thick, muscular walls that can expand and contract to accommodate the changes in blood pressure that occur as blood is pumped from the heart. The largest artery in the body is the aorta.

Veins are blood vessels that carry deoxygenated blood back to the heart from the body’s tissues and organs. Unlike arteries, veins have thinner walls and are less muscular. Veins contain one-way valves that help prevent blood from flowing backward as it travels toward the heart. The largest vein in the body is the vena cava.

Capillaries are tiny, thin-walled blood vessels that connect arteries and veins. They are responsible for the exchange of oxygen, nutrients, and waste products between the blood and the body’s tissues. Capillaries have thin walls that allow molecules to diffuse in and out of the bloodstream. The walls of capillaries are so thin that red blood cells have to pass through them in single file.

In summary, arteries carry oxygenated blood away from the heart, veins carry deoxygenated blood back to the heart, and capillaries are responsible for the exchange of molecules between the blood and the body’s tissues.