Which artery carries oxygen-free blood

Which veins carry oxygen-free blood?

The heart pumps oxygenated blood through the arteries, which then enter the tissue through tiny capillaries. Once the oxygen has diffused into the cells, carbon dioxide binds to the red blood cells instead.
Now the blood has very little oxygen and a lot of carbon dioxide. It is carried back to the heart by veins (the largest of which is the vena cava) to be pumped into the lungs.

This is where things get a little strange. Previously, every vessel of oxygenated blood was an artery, while every vessel of oxygen-free blood was a vein. It is the other way around with the lungs. The pulmonary artery carries deoxygenated blood to the lungs, where it is oxygenated before being returned to the heart by the pulmonary vein.

Since there are these two exceptions, it is best to think of veins as vessels that travel into the heart (bringing oxygen-free blood into normal and oxygen-rich blood after traveling to the lungs) and arteries (going out into the rest of the heart). usually get into the body with oxygenated blood and into the lungs to supply blood with oxygen).

In summary, it can be said that veins almost always carry oxygen-free blood, unless they lead to the heart via the lungs (pulmonary veins).

Hope that helps; Please let me know if there is anything else I can do or if something needs to be clarified 🙂