State the differences between artery, vein and capillary.​

Arteries	Veins	Capillaries
(i) These blood vessels have thick walls and carry blood from the heart to different body parts.​	(i)These blood vessels have thin walls and carry blood from different body parts to the heart. ​	(i) These blood vessels are narrow and have very thin walls, they connect arteries and veins. ​
(ii) They do not have valves. ​	(ii) They have valves and prevent backflow of blood.​	(ii) They do not have valves.​
(iii) All the arteries carry oxygenated blood except the pulmonary artery. ​	(iii) All the veins carry deoxygenated blood except the pulmonary vein.​	(iii) As it connects arteries and veins, therefore, it contains both oxygenated and deoxygenated blood.​
(iv) Artery can dilate or constrict depending on the regulatory requirement of the body.​	(iv) Veins cannot dilate or constrict.​	(iv) Capillary can dilate or constrict according to the requirement of the tissue.​