Why blood in pulmonary artery is voilet but in pulmonary vein is scarlet?

The blood in the pulmonary artery is violet because it is not oxygenated, while the blood carried by the pulmonary veins is oxygenated and its color is scarlet.

Explanation:

Under normal conditions, the arteries carry oxygenated blood, giving it a dazzling red or scarlet color, while the veins carry non-oxygenated blood —called venous blood— of a purplish and dark red color.

The only exceptions are the pulmonary arteries and veins

Pulmonary arteries carry non-oxygenated blood from the right ventricle to the lungs. They are the only arteries that carry non-oxygenated blood.Pulmonary veins carry oxygenated blood from the lungs to the left atrium, being the only veins to carry blood with oxygen.

This is why in the pulmonary arteries the blood is violet, and in the pulmonary veins the blood is scarlet.

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