State the differences between artery, vein and capillary.

Arteries

Veins

Capillaries

These are tough, thick and comprises

of elastic tubes.

Veins are thin-walled and comprises of

non-elastic tubes.

Capillaries are very thin-walled tubes.

They contain a narrow lumen.

They contain a wide lumen.

Only RBC can pass through lumen.

Blood is carried away from the heart to various organs at high

pressure.

Blood id transported to the heart from various organs at low

pressure.

Blood is carried from arteries to veins.

Valves are absent.

Valves are present to

prevent backward flow of the blood.

Valves are absent.

They transport only oxygenated blood (except for the pulmonary artery).

They transport only deoxygenated blood (except for the pulmonary vein).

They exchange oxygen, carbon dioxide, water and salts between the blood and the

surrounding tissues.