Four functions supported by blood cells and plasma

1. Transport: Blood conveys oxygen and nutrients, and removes waste products

The main blood constituents that perform this function are red blood cells and plasma. Red blood cells include an iron-containing protein called hemoglobin, which carries oxygen throughout the body. Insufficient hemoglobin is the main cause of anemia. Plasma contains a protein called albumin, which supplies nutrients and removes waste products.

2. Biological defense: One of blood’s functions is to protect the body against pathogens such as microbes, viruses and other disease-causing foreign bodies (immunological function)

This job is performed mainly by white blood cells (leukocytes). Enzymes bound to granules inside the white blood cells digest the proteins of bacteria and other pathogens. In addition, lymphocytes produce antibodies if there is an immune reaction to foreign material.
If white blood cell function is compromised, the body becomes more vulnerable to infectious diseases and other pathological conditions. Abnormal functioning of white blood cells can cause allergies and autoimmune diseases (where the body’s own immune system attacks the body itself).

3. Coagulation: Blood collects and clots at a wound site to stop bleeding

Platelets and fibrinogen in plasma play this role. When a blood vessel wall is damaged, platelets temporarily plug the wound while converting the coagulant fibrinogen into mesh-like fibrin to clot the blood and prevent further blood loss.

4. Regulation of internal environment: Blood carries heat throughout the body and helps maintain body temperature and fluid balance.

Blood heats the body and helps disperse excess heat in order to maintain a steady body temperature that is necessary to support life. It also helps maintain the balance of water between the blood itself (within the blood vessels) and the body (outside the blood vessels). Edema occurs if this balance is lost and fluid accumulates in tissues outside the blood vessels.

Column: Blood groups and types: Blood group is determined by the shape of antigens on the surface of red blood cells

Blood group differences and transfusion compatibility

Blood group AB individuals can receive transfusions from donors having group A, B or O blood. Group A and group B are mutually incompatible. Since group O blood cells have no antigens, group O blood can be donated to any other group. However group O individuals can only receive transfusions of blood from other group O individuals. Besides these ABO groups, blood is also classified by Rh (Rhesus) type. Medical science does not recognize any relationship between blood group and personality traits.

Blood group classification systems are based on antigens on the surface of red blood cells. The most significant of these systems, ABO, was discovered by Karl Landsteiner in 1900. It classifies blood by antigens A and B on the red blood cell surface. The presence, absence or combination of these antigens determines the classification of blood as group A, B, AB or O, as shown in the chart here. These blood groups are also associated with antibodies in the blood plasma for particular antigens. For example, a blood group A individual has antibodies that react to B antigens (so they are called anti-B antibodies).

Blood Group Antigens on Red Blood Cells Antibodies in Plasma
A A antigen anti-B
B B antigen anti-A
AB A and B antigen zero antibodies
O zero antigen anti-A and anti-B

If red blood cells having A antigens are donated to an individual having anti-A antibodies, the recipient’s immune system will attack the blood as a foreign material, causing agglutination (clumping). Therefore, when blood transfusion is necessary, the donated blood must be of the same group as the recipient’s blood or of a compatible group, that is, one that does not have an antigen on the red blood cell surface that will cause antibodies in the recipient’s blood plasma to react.

Patients and Families

For the general public: An introduction to therapies and Asahi Kasei Medical’s approach.

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A basic explanation of blood constituents and their functions, and how these relate to removal of harmful substances through therapeutic apheresis.

About Blood Purification Therapy

About the life-supporting functions of blood and therapies that utilize these functions.

We are restricted by law from replying to inquiries regarding the therapeutic effects or side effects of therapeutic methods or our products. Please consult with your healthcare provider or a medical institution.

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