Synonyms in a broader sense
Blood cells, blood plasma, blood cells, erythrocytes, thrombocytes, leukocytes
Introduction
The function of the blood is primarily as a transport mechanism. This includes nutrients that are transported from the stomach via the liver to the respective target organ, e.g. muscles. Furthermore, metabolic products such as urea as the end product are transported via the blood to the respective excretion organs.
Transport function of the blood
Other substances are transported via the blood:
- Gases such as oxygen, carbon dioxide or nitrogen
- Active ingredients such as vitamins, enzymes and hormones
- Defensive substances
- Water
- Heat
- Electrolytes
Blood volume
The amount of blood in the human body is about 7-8% of the body mass. For a 70 kilo man this corresponds to about 5 litres of blood. For younger children the proportion is about 8-9%, for swingers about 10%.
A longer stay at higher altitudes also causes an increase in blood volume (hypervolemia). A reduced blood volume compared to the normal value is called hypovolemia and occurs in cases of heavy sweating or acute blood loss. A healthy adult person can easily tolerate a blood volume loss of 10-15%. An acute blood loss of more than 30% results in hypovolemic shock.
Blood Cells
About 55% of the blood volume consists of blood plasma, 45% of blood cells. The blood cells float in the yellowish blood plasma. The proportion of blood cells in the blood is called the haematocrit value.
The normal haematocrit value for men is about 45%, for women about 41% and for children about 37%. If the haematocrit value of the blood rises, the blood becomes more viscous and the viscosity (internal friction) increases. This increases the blood flow resistance. A distinction is made between blood cells:
- Red blood cells (erythrocytes)
- White blood cells (leukocytes)
- Blood platelets (thrombocytes)
Blood groups
AB0 – blood group system is based on gycolipid antigens (A and B). People whose red blood cells only have the antigen A or B have the blood group A or B. People who have both the antigen A and B have the blood group AB.
If one does not have an antigen, one speaks of blood group 0. Blood groups of Europeans: Compatible blood transfusions Blood groups A and B are only compatible for blood of the same blood group and blood group 0. Blood group AB is compatible with all blood groups.
Blood group 0 is only compatible with blood group 0. If a transfusion is given with the wrong blood group, the blood will clump together and cause anaphylactic shock. Rhesus blood group system The name is based on the discovery of the antigen in the blood of the rhesus monkey.
People whose red blood cells have the D- antigen are called RH+. If the D- antigen is missing, one speaks of RH-. – 45% blood group 0
- 40% blood group A
- 11% blood group B
- 4% blood group AB
