Arteries | Vein | Capillary |
Arteries carry oxygen rich blood from heart to all the parts of body except pulmonary artery that carries deoxygenated blood to lungs. | Vein takes carbon dioxide rich blood from all parts of the body back to the heart except pulmonary vein that brings oxygen rich blood from lungs. | Capillaries are very thin blood vessels and they connect arteries and veins. They supply blood to the tissues. |
Thick walled | Thin walled | Very thin, one cell thick. |