Human Blood Groups Flashcards
(21 cards)
ABO blood types were identified…
… in 1900 by Karl Landstein (1930 Nobel laureate)
Blood groups are determined by…
…agglutinogens
What are agglutinogens?
Specific glycoproteins on red blood cell membranes or surface antigens on RBCs. All RBCs in an individual carry the same specific type of agglutinogens.
What are antigens?
Substances that trigger a defensive response from the leukocytes of the immune system when there is a perceived threat.
ABO blood groups and their agglutinogens
Type A = A
Type B = B
Type AB = A and B
Type O = Neither A nor B
What produces the antibodies that cause agglutination?
Certain B lymphocytes called Plasma Cells
Explain agglutination
- Incompatible blood is infused and RBCs with foreign antibodies appear in blood stream
- Immune response is triggered where antibodies attach to RBCs and cause them to adhere to one another
Shape of agglutination antibodies
Y-shaped
Effects of agglutination
Blocked blood vessels, interrupting transport. Degraded clumps release excess haemoglobin which may overwhelm kidneys and cause kidney failure
What are the antibodies that cause agglutination called?
Agglutinin; they are pre-formed antibodies
Type O blood contains both A and B agglutinis, true or false?
True
What is agglutination?
Aggregation and lysis of incompatible RBCs
Explain RH blood grouping
Here, we classify blood groups based on the presence of Rh agglutinogens other than A/B agglutinogens
RH blood group stats
85 of white - Positive
95% of American blacks - Positive
Almost all African blacks - Positive
Rh positive and negative blood
Rh positive has Rh agglutinogens
Rh negative doesn’t have
Rh positive has Rh negative agglutinins and vice versa
Agglutinins against Rh-positive RBCs are produced…
…after Rh-negative blood sees Rh-positive RBCs.
Difference between RH blood and ABO blood agglutins
RH is not pre-formed, it only forms on Rh negative’s exposure to Rh antigen. ABO agglutinin is pre-formed.
What is Rh sensitization?
The process whereby Rh agglutins are formed in Rh negative individuals in response to introduction of Rh positive blood
What is haemolytic disease of the newborn?
When Rh negative mother with Rh agglutins carries Rh positive child and these agglutins destroy the foetal RBCs
Effects of haemolytic disease of the newborn?
Anaemia
Still birth
Treatment of HDN
Use of anti-Rh gamma globulin to mask Rh agglutinogens
