Blood groups and transfusions Flashcards
What is an antibody?
Protein produced by the immune system in response to a specific antigen, to neutralise and destroy it.
What is an antigen?
Specific proteins our body produces to allow white blood cells to distinguish between self and non-self.
What is agglutination?
The clumping of microbes or blood cells caused by antibodies and the mixing of incompatible blood types.
How does coagulation occur?
-clotting factors in plasma
formation of insoluble protien threads=fibrins
- fibrins from a mesh, trap blood cells, plasma, platelets
- mesh with trapped material=clot/thrombus
- threads stick to broken vessels, hold clots in place= a scab
What is clot retraction?
- fibrin network contracts which pulls the damaged vessels together
- as retraction occurs, fluid (serum) squeezes out of clot
- clot dries= scab
- scab prevent entry of infecting micro-organisms
What are clotting factors?
Chemical substances in plasma that allow blood to clot (always proteins)
What is haemophilia?
An inherent disorder where blood clumps slowly or not at all
How does blood clotting occur? (3)
- Vasoconstriction
- Platelet plug
- Coagulation
How does a platelet plug function?
-Blood vessels have smooth internal walls that become rough when damaged
-platelets stick, then attract others which results in a build up
-plug reduces blood loss
-releases vasoconstrictor like substances to enhance vessel constriction of lumen
Platelet plugs stop small almost daily tears
Function of platelets
Adhere to lining of damaged blood vessel and form a scaffold for coagulation of blood to form a clot (scab)
How does vasoconstriction function?
- small arteries walls constrict immediately after being damaged to reduce blood flow
- so, blood less decreases
What are vasoconstrictors?
- Decrease the lumen of a blood vessel
- restriction of blood flow
What are vasodilators?
- substances that relax smooth muscle surrounding arteries
- increases lumen size=increase blood flow
What are the types of blood transfusions?
- Whole blood
- Platelet concentrate
- red cell concentrate
- cryoprecipitate
- immunoglobulins
- autologous transfusion
What is whole blood transfusion?
-blood is taken from a donor
-chemical is added to prevent clotting
For sever blood loss in a patient
What is platelet concentrate transfusion?
-after being separated, portion of blood containing platelets is given to a recipient
For abnormal platelets + reduced platelet number
What is red blood cell concentrate transfusion?
Most used component
-blood is spun in centrifuge at high speed
-heavy RBC’s sink while light plasma stays at the top (due to being more dense)
For heart disease or ammonia patients
What is cryoprecipitate transfusion?
-Freezing plasma
-thawing it out slowly
-when thawed, cryoprecipitate remains solid (contains clotting factors)
For haemophilia treatment or severe blood loss
What is autologous transfusion?
When own patients blood is used as treatment
- collected 4 weeks prior to op.
- eliminates disease risk of blood mismatch
What is immunoglobulins transfusion?
-group of proteins is extracted that shares characteristics similar to antibodies
-given to antibody deficient patients
For tetanus treatment and people with no disease immunity
Info on blood type A
- A antigens
- B antibodies
- Can receive B and O
- Can donate to A and AB
Info on blood type B
- B antigens
- A antibodies
- Can receive B and O
- Can donate to B and AB
Info on blood type O
- no antigens
- A and B antibodies
- Can receive 0
- Can donate to AB, A, B, O
Info on blood type AB
- A and B antigens
- no antibodies
- Can receive A, B, O, AB
- Can donate to AB
Info on Rh blood groups
- Has protein, ABO doesn’t
- Rh positive people: no antibodies, Rh antigens
- Rh negative people: anti-Rh antibodies, no antigens
