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AB 9 Blood groups

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Health and disease – Immunity
Blood groups and blood transfusions
Pre-task: Match the German words with the English translation and enter them in the table.
English
German
Spender
Verklumpung
verklumpen
AB0 Blutgruppen
Rhesusfaktor
Gewebetransplantat
Blutübertragung
kompatibel, (zusammen-)passend
Inkompatibel, unverträglich
(starke) Blutung
Hämolyse
Empfänger
Operation
übertragen
blood transfusion
donor
recipient
tissue transplant
AB0 groups
rhesus factor
haemorrhage
surgery
to transfuse
compatible
agglutination
haemolysis
agglutinated
incompatible
to clump
The transfusion of blood from one person (the donor) to another (the recipient) is
the most common ‘tissue transplant’. It has to be carried out carefully because
red blood cells carry antigens on their surface membrane, and blood plasma carries antibodies to
these antigens. The blood types of the donor
and recipient must be carefully matched. This
matching can ignore the antibodies of the
donor, but must consider the antibodies of the
recipient and the antigens of the donor.
There are two sets of antigen-antibody
interactions to consider. One concerns the AB0
groups; the other concerns the rhesus factor.
These interactions, and the effects they have on
blood transfusion are outlined in the following.
AB0 groups and blood transfusion
The AB0 blood grouping is based on:


two antigens called agglutinogens, symbolized as A and B, which are genetically determined
carbohydrate molecules carried on the surface membrane of the red blood cells
two antibodies called agglutinins, anti-A and anti-B, carried in the blood plasma.
A blood transfusion may be necessary to make up blood volume following haemorrhage or during
surgery. Only compatible blood should be transfused, or agglutination (clumping of red blood cells)
and haemolysis (the breakdown of red blood cells) may occur. Agglutinated (clumped) cells may block
capillaries and cause kidney or brain damage, or even death. Haemolysed cells ‘leak’ haemoglobin
(protein that transports oxygen) so oxygen transport is affected.
An incompatible transfusion: blood group B red blood cells of the donor are clumped
by anti-B agglutinins (antibodies) in plasma of blood group A of the recipient.
Health and disease – Immunity
Blood groups and blood transfusions
Sketch of a red blood cell showing both A and B agglutinogen (antigen):
Antibody anti-A:
antibody anti-B:
Tasks
Use the information from above and…
1. …draw the correct blood cell (showing either antigen A, B, 0 or both A and B) and the correct
antibody into the shaded boxes.
2. …conclude which transfusions cause clumping of red blood cells (agglutination). Use the
following symbols:
(+) blood clumps
(-) blood does not clump
(Donor)
red blood cells of the blood group:
(Recipient)
Blood plasma of the blood group
A
B
AB
0
A
(anti-B)
B
(anti-A)
AB
(neither)
0
(both)
Use the information in the table and your knowledge and answer the following questions:
3. Which blood group is known as the universal recipient and which is known as the universal
donor? Give reasons for your answers.
4. Explain why it is important to screen all donated blood.
Extra: Do research on the rhesus (Rh) system of blood grouping.
- What is rhesus positive (Rh+) and rhesus negative (Rh-)?
- Explain when a blood transfusion from a Rh+ donor to a Rh- recipient can be dangerous?
- Explain why it can be dangerous for a rhesus positive baby (Rh+) to be carried by a rhesus
negative mother (Rh-).
Health and disease – Immunity
Blood groups and blood transfusions
Use the information from above and…
1. …draw the correct blood cell (showing either antigen A, B, 0 or both A and B) and the correct
antibody into the shaded boxes.
2. …conclude which transfusions cause clumping of red blood cells (agglutination). Use the
following symbols:
(+) blood clumps
(-) blood does not clump
(Recipient)
Blood plasma of the blood group
(Donor)
red blood cells of the blood group:
A
B
AB
0
A
(anti-B)
-
+
+
-
B
(anti-A)
+
-
+
-
AB
(neither)
-
-
-
-
0
(both)
+
+
+
-
Use the information in the table and your knowledge and answer the following questions:
1. Which blood group is known as the universal recipient and which is known as the universal
donor? Give reasons for your answers.
Universal recipient: AB, since its plasma contains no agglutinins (antigens) to clump donor red
blood cells.
Universal donor: 0, since its red blood cells do not carry agglutinogens to be clumped by
recipient antibodies.
2. Explain why it is important to screen all donated blood.