In the diagrams, we conventionally show veins in blue. What is the actual colour of the blood flowing through the following?

(i) In arteries

(ii) In veins

(iii) In capillaries

(i) The actual colour of the blood flowing through the artery is bright red.

Note: the blood carried by artery is from the heart to the organs and thus is oxygenated and is bright red in colour.

(ii) The actual colour of the blood flowing through the veins is dark red.

Note: the blood carried by vein is from the organs to the heart and thus is deoxygenated and is dark red in colour.

(iii) The actual colour of the blood flowing through the capillaries is bright red.

Note: the blood carried by capillaries is from the heart (via arteries which bifurcates into capillaries) to the organs and thus is oxygenated and is bright red in colour. It then leaves the organs and re – fuses into veins and carry the deoxygenated blood.