Page 119 - Biology Form Two

Biology for Secondary Schools

Blood transfusion is the transfer of transfusion considers the reaction
blood from the donor to the recipient. between the antigen of the donor’s
It is necessary to replace blood when blood and antibodies of the recipient’s
the recipient has a blood disorder or blood.
has lost a lot of blood due to surgery
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or an accident. For blood transfusion Individuals with blood group AB are
to be successful, the blood of the called universal recipients. They can
donor and that of the recipient must receive blood from people of any blood
be able to mix without agglutination. group because they have no antibodies a
When this happens, the two blood and b in their blood. However, they can
samples are said to be compatible, but only donate blood to someone with blood
if the blood samples are incompatible, group AB. Those with blood group O are
agglutination occurs and that can cause universal donors. They can donate blood
death. Blood compatibility depends on to people of all blood groups because
the blood groups of the donor and the they have no antigen. However, they
recipient. For example, if a person of can only receive blood from someone
blood group A receives blood from a with blood group O because the plasma
person of blood group B, the recipient’s contains both antibodies a and b. Table
body produces antibodies against 5.4 shows compatibility of different
antigen B. This is because the antigen blood groups.
is seen as foreign material. Therefore,

Table 5.4: Compatibility of blood groups
Donor’s blood Recipient’s blood group
group
A B AB O
A ü û ü û

B û ü ü û
AB û û ü û
O ü ü ü ü
Key:
ü means compatible
û means incompatible

If blood from a rhesus positive person is transfused to a rhesus negative person,
the recipient produces rhesus antibodies. If such a transfusion is done for a second
time, massive agglutination can occur. This can lead to death.

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