The most common cell in your bloodstream gives blood its red color and is thus called a red blood cell. Just one drop of your blood contains hundreds of millions of such cells. When viewed through a microscope, they look like doughnuts with a depressed center instead of a hole. Each cell is packed with hundreds of millions of hemoglobin molecules. Each hemoglobin is, in turn, a beautiful spherical structure made up of about 10,000 hydrogen, carbon, nitrogen, oxygen and sulfur atoms, plus four heavier atoms of iron, which gives blood its oxygen- carrying ability. Hemoglobin facilitates the transport of carbon dioxide from the tissues to the lungs, where it is exhaled.
Another vital part of your red blood cells is their skin, called membrane. This marvelous covering enables the cells to stretch into thin shapes so as to pass through your thinnest blood vessels and thus sustain every part of your body.
Manufacturing of the red blood cell is done in the bone marrow. Once a new one is created, it enters your blood stream; it may circulate through your heart and body more than 100,000 times. Unlike the other cells, the red blood cells have no nucleus. This gives them more space to carry oxygen and makes it lighter, which helps your heart to pump millions of red blood cells throughout your body. However, lack of a nucleus results to inability to renew their internal parts. Thus, after 120 days, your red blood cell begins to deteriorate and lose their elasticity.
The large white blood cell called phagocytes consumes these worn-out cells and spit out the iron atoms. The scarce iron atoms attach themselves to transport molecules that take them to your bone marrow to be used in the manufacture of new red cells. Every second, your bone marrow releases two to three million new red blood cells into your bloodstream!
If your trillions of red blood cells were suddenly to stop functioning, that entails death within minutes. No doubt, you will agree with me, the essence of this marvelous creation.