Blood groups/ types Flashcards
what are the four main reasons someone may require a blood transfusion?
if a person is suffering from…
- excess blood loss
- anaemia
- leukaemia
- haemophilia
define transfusion
the transfer of blood, or some of the components of blood, into the circulation of a person.
the surface area of red blood cells is coated with…
sugar and protein molecules that are able to stimulate the immune system.
these molecules are called antigen and the proteins produced by the immune system is called an antibody.
define antigen
any substance capable of causing the formation of antibodies when introduced into the tissue.
define antibody
a substance produced in response to a specific antigen; it combines with the antigen to neutralise or destroy it.
what are the two sugar antigens involved in ABO blood groups?
antigen A and antigen B
how is a persons blood group determined?
by DNA and so is therefore inherited.
when does a persons body produce antibodies?
a persons body is able to recognise their own antigens and will not produce antibodies for them. however, they will produce antibodies for antigens that are non-self.
Therefore a group A person can only produce antibody anti-B, a group B person can only produce antibody anti-A, a group AB person can produce neither and a group O person can produce both.
what are Rh antigens
proteins
Rh postive vs Rh negative
a person with Rh antigens is said to Rh positive; a person without Rh antigens is said to be Rh negative.
An individual without Rh antigens is able to produce an anti-Rh antibody that reacts against those antigens. Rh positive individuals cannot produce Rh antibody.
what happens if incompatible blood types mix?
it will cause erythrocytes to clump together, or agglutinate.
if the receivers blood contains, or is able to make, antibodies against the antigens on the donors red blood cells, the foreign cells will clump together and disintegrate.
types of transfusions
- whole blood
- red cell concentrates
- platelet concentrates
- cryoprecipitate
- immunoglobulins
- autologous transfusions
who can blood group A donate to and who can they receive from?
donate to… A and AB
receive blood from… A and O
who can blood group B donate to and who can they receive from?
donate to… B and AB
receive blood from… B and O
who can blood group AB donate to and who can they receive from?
donate to… AB
receive blood from… A, B, AB, O
who can blood group O donate to and who can they receive from?
donate to… A, B, AB, O
receive blood from… O
whole blood transfusion
blood taken from the donor. it has a chemical added to prevent clotting. used mainly in cases of severe blood loss.
red cell concentrates transfusion
the most widely used component of blood. made buy centrifuging whole blood to separate cells from plasma. used for patients suffering heart disease or anaemia.
platelet concentrates transfusion
given to patients who have abnormal platelets or a reduced number of platelets.
cryoprecipitate
obtained by freezing plasma and then thawing it. once plasma is thawed the cryoprecipitate remains solid, containing many of the substances required for blood clotting.
treats some forms of haemophilia, but used mostly for severe blood loss.
immunoglobulins
group of proteins that act as antibodies. antibodies are extracted from plasma of suitable donors.
eg. tetanus immunoglobulin may be used to treat tetanus.
autologous transfusion
when the patients own blood is used. blood is collected 4 weeks prior to an operation. they eliminate the effect of possible disease.
