Introduction
The erythrocytes (red blood cells) are flat, nucleusless discs with a size of about 8 micrometers and are the main representatives in the blood of vertebrates. Their biconcave shape (wider at the edges than in the center) and size allow optimal flow properties in narrow capillaries. Inside the dented center is the red blood pigment hemoglobin.
The total surface area of all erythrocytes in the human body is about the size of a soccer field. The erythrocytes consist of 60% water and 40% protein. The protein portion consists of 32% hemoglobin. (globin and hemochromogen, to which oxygen can be loosely attached) The lifespan of erythrocytes is about 4 months.
Values of the erythrocytes
In one cubic centimeter (cm3) there are about 5 million erythrocytes. This corresponds to about 4.5 – 6 billion per ml. for men and about 4 – 5.5 billion per milliliter for women.
The total number of erythrocytes present in the blood is about 25 to 30 trillion. The lifespan is about 120 days, the new production is about 1% per day. The development time is about 7 days.
Disassembly
The erythrocytes are broken down in the liver and spleen but also in other tissues (see in case of a haematoma). A deficiency of hemoglobin, independent of the erythrocyte deficiency, leads to a reduction of the oxygen transport capacity and is called anemia.
Place of education
If too little oxygen is available in the tissue (hypoxia), the hormone erythropoietin (EPO) is released from the kidney tissue. This hormone causes red blood cells to be newly formed in the bone marrow. The place of formation of erythrocytes is the red bone marrow (tubular bone, sternum, vertebrae). Approximately 160 million new red blood cells are formed every minute, which corresponds to approximately 1 liter of blood per month. Erythropietin can be produced more synthetically and is used in doping.
Function
The erythrocytes can be regarded as a kind of transport container for hemoglobin. The main function of hemoglobin is to transport oxygen by binding O2 to the iron atom. The blood enriched with oxygen is transported via the arterial circulation to the successful organ.
From there, the carbon dioxide-rich blood returns through the venous circulation. However, hemoglobin is only partly responsible for the return transport of CO2. The gas exchange takes place in the lungs.
