Question

What veins carry deoxygenated blood?

Answer 1

Hint: Veins are a part of the cardiovascular system of the human body which carry blood to the heart from every other organ. They are depicted blue in colour because almost all veins carry deoxygenated blood with two exceptions.

Complete answer:
The human cardiovascular system’s purpose is to transport oxygen, carbon dioxide, nutrients, hormones, etc. to and from the heart and other organs of the body. Heart, blood, blood vessels, lymph and lymph vessels are the major components of this system. While the heart pumps blood to every organ of the body, this blood is transported to those organs via blood vessels. There are 3 kinds of blood vessels found in the human body:
-Arteries
-Veins
-Capillaries
Arteries can be defined as the vessels that carry blood away from the heart. Similarly veins are the vessels that carry blood towards the heart.
Oxygenated blood pumped from the heart travels to other organs of the body in arteries where they enter the smallest blood vessels, capillaries. This is the site of exchange of gases, nutrients and waste materials between tissue and blood. As the oxygen is taken up by the tissues, carbon dioxide is given in exchange, rendering the blood devoid of oxygen. This blood is called deoxygenated blood and it is transported back to the heart in veins to be pumped again.
Veins from throughout the body carry deoxygenated blood from the tissues to the heart, except the pulmonary vein. Since all veins carry blood to the heart with no exception, only the pulmonary vein transports oxygenated blood from the lungs to the heart, while every other vein carries deoxygenated blood.

Note:
Heart is only responsible for pumping blood throughout the body, lungs are the organs where blood is oxygenated.
The only other vein that carries oxygenated blood is the umbilical vein which carries blood from placenta to the developing foetus in pregnant women.

VENOUS SYSTEM