The pigment responsible for carrying oxygen in the blood is haemoglobin. Haemoglobin is a complex protein found in red blood cells. Its primary function is to transport oxygen from the lungs to the rest of the body and return carbon dioxide from the body to the lungs for exhalation. Each haemoglobin molecule can bind to four oxygen molecules, allowing it to carry and efficiently distribute a large amount of oxygen throughout the body.
Here's a simple explanation of how it works:
Haemoglobin binds with oxygen in the lungs, forming oxyhaemoglobin, which gives blood its bright red color.
This oxyhaemoglobin travels through the bloodstream to tissues and organs, where it releases the oxygen for cell respiration.
As it releases oxygen, it picks up carbon dioxide, a waste product from cells, and becomes deoxygenated, giving it a darker color.
The deoxygenated blood returns to the lungs, where carbon dioxide is released, and the cycle repeats.
It is essential to note that while oxyhaemoglobin is simply haemoglobin that has combined with oxygen, the fundamental oxygen-carrying pigment itself is still haemoglobin.