1. Blood Constituents & Blood Types
Topic 12 – Red Alert

2. Blood Constituents
There are about 5 litres of blood in the human body.
The blood is made up of solid and liquid components.

3. Solid Components
Red blood cells – These are the most common type of blood cell. On their surface is a protein, hemoglobin, which plays a role in the transportation of oxygen and carbon dioxide. Deoxygenated hemoglobin is dark red, whereas oxygenated hemoglobin is bright red.
White blood cells (or leucocytes) –there are several types of white blood cells and they each contain a nucleus. Some white blood cells protect the body; they neutralize antigens (bacteria, viruses, or other foreign substances). Other white blood cells are responsible for ridding the body of dead or damaged cells.

4. Solid Components
Platelets – they contain a chemical substance that is responsible for blood coagulation. When someone is injured and bleeding the platelets gather where the injury is in order to help produce fibrin, which causes blood clotting.

5. Liquid Components
Plasma – the plasma is responsible for the majority of the blood volume. It contains the red and white blood cells, platelets, nutrients, antibodies, hormones and waste and is responsible for transporting them throughout the body.

6. Blood Types
Agglutinogens are antigens on the surface of red blood cells that can trigger a defensive reaction if a foreign substance is introduced in the blood stream. Not all red blood cells have agglutinogens and there are several types.
We will be focusing on the ABO and Rhesus blood typing system. In the ABO blood typing system, there are two types of agglutinogens:
agglutinogen A
agglutinogen B

7. Agglutinogens
A person with agglutinogen A on the surface of their red blood cells has blood type A.
A person with agglutinogen B on the surface of their red blood cells has blood type B.
If a person has both A and B agglutinogens present on the surface of their red blood cells, then their blood type is AB.
If there are no agglutinogens present on the surface of the red blood cells, then the person has blood type O.

8. Agglutinogens
The Rhesus (Rh) factor is another type of agglutinogen that may or may not be present on the red blood cells.
If a person has the Rhesus factor on their red blood cells, then their blood type is positive (+).
If a person does not possess the Rhesus factor on their red blood cells, then their blood type is negative (-).

9. Agglutinins
The plasma contains agglutinins or antibodies that act against foreign agglutinogens that enter the blood stream. The agglutinins will bind to foreign agglutinogens to neutralize them.
For example:
A person with type A+ blood will have agglutinogens A and Rh+ on their red blood cells. In the plasma, there will be anti-B agglutinins to recognize the B agglutinogens that are not present on their red blood cells.
A person with type O- blood will have no agglutinogens present on the surface of their red blood cells. Their plasma will contain anti-A, anti-B, and anti-Rh.

10. Transfusion
The transfer of a blood product from one person to another is called a blood transfusion.
It is important to know the blood type of each individual because of the agglutinogens present on the red blood cells and the agglutinins present in the plasma.
If there are incompatibilities, this will cause agglutination (or coagulation, forming clots) of the red blood cells.

11. Compatibility
Blood compatibility is when a blood transfusion can occur will donor blood that is the same type as the recipients blood without resulting in agglutination.
Rule: We can only receive blood with the agglutinogens that we already have. If not, agglutination will occur.

12. Compatibility
Blood type O- is referred to as the universal donor because there are no agglutinogens present on the surface of the red blood cells.
Blood type AB+ is referred to as the universal recipient because there are no agglutinins (antibodies) present in the blood plasma.

13. Compatibility Blood Type Can give to Can receive from A-
A+, A-, AB+, AB-
A-, O- A+
A+, AB+
A+. A-, O+, O- B-
B-, B+, AB-, AB+
B-, O- B+
B+, AB+
B+, B-, O+, O-
AB-
AB-. AB+
AB-, A-, B-, O-
AB+
ALL O- O+
O+, A+, B+, AB+
O+, O-