Blood Group

Blood is an essential constituent of the human body. It makes up almost seven per cent of the body weight. It differs according to weight and size of the body, gender, place of living, etc. The blood type varies from human to human, and it is differentiated based on the presence or absence of antigens on the RBC’s surface. RBC means red blood cells. An antigen is a substance that produces an immune response in the body. We will learn more about blood group meaning in the sections ahead.

Composition of blood 

In this section, we will talk about the composition of blood. We will also understand how a blood type is classified. Blood consists of the following components:

• Red blood cells
• White blood cells
• Platelets
• Plasma

Red blood cells: These carry oxygen from the lungs to other tissues in the body. And they carry carbon dioxide from the body’s tissues back to the lungs.

White blood cells: These help the body protect and fight against various infections.

Platelets: These are present in the bone marrow. They help in the clotting of the blood.

Plasma: It is the fluid part of the blood that is yellow. It carries materials across different parts of the body.

Now, antigens can be classified according to the different blood type systems into:

• Proteins
• Carbohydrates
• Glycolipids
• Sugars

The functions of antigen are as follows:

• To carry substances in and out of the cells.
• To identify unnecessary illness-causing cells.
• To keep the structure of the RBCs intact.

Popular blood group systems

• ABO System: It is one of the most popular blood type systems. Various blood types are:
  • Group A: In this, the red blood cells contain an A antigen. The plasma contains an anti-B antibody.
  • Group B: In this, the red blood cells contain a B antigen. The plasma contains an anti-A antibody.
  • Group AB: In this, the red blood cells have both A and B antigens. The plasma consists of neither anti-A nor anti-B antibodies.
  • Group O: In this, the plasma contains both anti-A and anti-B antibodies. The red blood cells contain neither A nor B antigens.

• The rhesus system: It is the next most important blood type system. It currently has 50 antigens.
  • Rh-Positive: If the surface of red blood cells contains the RhD antigen.
  • Rh-Negative: If the surface of red blood cells doesn’t contain the RhD antigen.

Doctors mainly consider both ABO and Rhesus systems while classifying the blood type. There are more types of such systems, but we will mainly talk about these two systems.

Different blood types

The antigens occurring on the surface of RBCs decide the blood type. Genes inherited from our parents decide the antigens.

The eight major types of blood group are:

• A+: Individuals having antigen A and RhD antigen.
• A-: Individuals having antigen A and no RhD antigen.
• B+: Individuals having antigen B and RhD antigen.
• B-: Individuals having antigen B and no RhD antigen.
• AB+: Individuals having antigen A, antigen B, and RhD antigen.
• AB-: Individuals having antigen A, antigen B, and no RhD antigen.
• O+: Individuals having neither antigen A nor antigen B and RhD antigen.
• O-: Individuals having neither antigen A nor antigen B and no RhD antigen.

There are many other blood types. But, mainly, the eight groups mentioned above are studied.

Universal Donors and recipients

Here, we will study the various factors which make a person eligible to donate or receive blood. The O- group contains neither A and B antigen nor RhD antigen. Therefore, this blood group can donate blood to any recipient. It is compatible with the other blood types, so it is safe. The individual having this blood type is a universal donor. A person not having RhD antigen can donate to an individual having blood with or without RhD antigen. Also, a person having RhD antigen can donate blood to a person having the same antigen.

Compatibility of different blood types

• A+: It can donate blood to people having blood groups A+ and AB+. Also, it can receive blood from O+, O-, A+, A-.
• A-: It can donate blood to people having blood types A+, A-, AB+, and AB-. It can also receive blood from A- and O-.
• B+: It can give blood to people having blood types B+ and AB+. It can also receive blood from B+, B-, O+, and O-.
• B-: It can donate blood to people having blood groups B+, B-, AB-, and AB+. It can also receive blood from B- and O-.
• AB+: It can donate blood to people having blood group AB+. It can also receive blood from everyone.
• AB-: It can donate to people having blood groups AB- and AB+. It can receive blood from a donor having AB-, A-, B- and O- blood groups.
• O+: It can donate to people having blood groups A+, B+, O+, and AB+. It can receive blood from O+ and O-.
• O-: It can donate blood to any individual. It can take blood only from O-.

Testing of blood types

It involves mixing of a person’s blood with substances having:

• A antibodies
• B antibodies
• Rh factor

The antibodies react differently, which results in incompatible blood clumps.

Conclusion

In this section, we learned about blood group meaning. We also studied the composition of blood. We briefly discussed the eight kinds of blood groups. Two main systems of the blood type were studied. We came across various interesting facts about different blood types. More information on different blood types can be gathered from credible and reliable online resources. You can also refer to the blood group lesson notes to gain sufficient knowledge about different types of blood groups in human beings.