How do the diameters of arteries veins and capillaries compare in size?

Arteries:

- Large diameter, typically ranging from a few millimeters (mm) to several centimeters (cm).

- They carry oxygenated blood away from the heart to the rest of the body.

Veins:

- Smaller in diameter compared to arteries.

- They range from a few millimeters in smaller veins to over a centimeter in larger veins like the superior and inferior vena cava.

- Veins carry deoxygenated blood back to the heart.

Capillaries:

- Microscopic vessels.

- Only a few micrometers (µm) in diameter.

- Capillaries form the smallest and most numerous vessels in the circulatory system, where the exchange of nutrients, oxygen, and waste products occurs between the blood and surrounding tissues.

In summary, arteries have the largest diameter, followed by veins, and then capillaries have the smallest diameter. This variation in size is essential for the efficient functioning of the circulatory system, ensuring that blood is properly transported throughout the body.