About blood

Blood forms the transport system of the body. It flows continuously to supply oxygen and nutrients to tissue and to remove waste products. It also plays an important role in the defense against pathogens in the body and ensures a constant body temperature. Blood is an important transport medium for hormones. So blood literally means life!

About half of the human blood is plasma. Blood plasma mainly consists of fluid and proteins. The other half of this blood consists of blood cells, namely: red blood cells, white blood cells and platelets. For example, the red blood cells transport oxygen and carbon dioxide through the body. The white blood cells make harmful substances and pathogens recognizable and harmless. Platelets provide crusting to a wound.

Red blood cells are different in size, number and build, in different animal species, as is shown in the photo. The different kinds of blood are all photographed at the same magnification. As a reference, the diameter of the human red blood cell can be taken, which is about 7.5 µm. Its thickness is about 2 µm.

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