blood system – blood group – physiology class

A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system, and some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens, that stem from one allele (or very closely linked genes), collectively form a blood group system. A total of 29 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).

ok! that’s the info i got fm the good old wiki~ now its time for my own research! reason of blood group is the presence of special glycoprotein in erythrocyte membrane.

antigen(physiologically) – substance contained in erythrocyte membrane (refer to figure above). the most important system is ABO system followed by Rhesus(Rh) system. each person has an individual antigenic structure.

[antigen(microbiologically) - any foreign subtance that can react with immune system to produce antibody]

agglutination - a version of immune reaction participated by antigen & antibody.

ABO system.

there r 4 group of blood according to ABO system; A, B, AB & O.

antigen of ABO system are; agglutinogen A, agglutinogen B, & agglutinogen H(not active,act as base, all people hv). they r water-insoluble glycoprotein. Antigen formation starts during 2nd month of embronic development & the greatest activity is during 8-10 years old..Antibody however, only start to develops during 2months of life; mostly due to reaction with antigen in foods.

agglutinins - antibody which are presence in blood plasma (can agglutinate with erythrocytes). there are two types; alpha (anti-A); which react with antigen A and beta (anti-B), react with antigen B. human blood can contains 1 or both or none agglutinin.

human blood never contain agglutinogen and agglutinin of the same type (agglutinogen A & agglutinin A or agglutinogen B & agglutinin B)

agglutination of erythrocyte – when agglutinogen of donor are combined with same agglutinin of recepient. occur during incompatible transfussion. antibody in plasma will react with agglutinogen in the surface of erytrocytes. the agglutinated erytrocytes block small vessels & capillaries; hemolysis of erythrocytes occur due to presence of hemolysin in incompatible agglutinogen of donor causing release of hemoglobin to plasma. free hemoglobin block kidney tubules. the symptoms include; headache, pain in joints, pain and dysfunction of kidney & liver which will lead to death.

Blood transfusion.

the main principle: transfer of blood of the same blood group.

principles of transfusion of blood to different group: 1) transfused blood should NOT contain identical agglutinogen of donor to identical agglutinin of recipient. 2) donor agglutinins are diluted when small(~500ml) volume of blood are transfused. (blood in human ~4.5 – 5L, so not enough agglutinins of donor – agglutination wont occur)

left: erythrocytes compatibility chart; right: plasma compatibility chart.

Method of bood transfusion.

1) before transfusion check ABO factor & Rhesus factor of recipient & donor.

2) then make cross test. (mix erythrocytes of donor n plasma of recipient & vice versa.) Check for agglutination cause by other factors.

3) then make biological test. tranfuse blood to the recipient 10-15ml fast. then stop for 3 minutes & check the patient. repeat this 3 times.

4) if no symptoms occurs (headache, respiratory problems, etc) then continue with full transfusion.

Rhesus system.

Many people also have a Rh factor on the red blood cell’s surface. This is also an antigen and those who have it are called Rh+. Those who haven’t are called Rh-. A person with Rh- blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance). But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh- blood without any problems. [from nobelprize.org]

Rhesus factors are = C,D,E,c,d,e. each person has one of each of the 3pairs. D antigen is widely prevalent and more antigenic than other Rh antigens. erythrocytes with D antigen, Rh+ (~85%); Rh- (~15%). antibody of this factor only develop after blood transfusion.

Rhesus conflicts:

1) transfusion of Rh+ to Rh- person, for 1st time no reaction occurs but Rh- person will develop anti-Rh which can cause agglutination. if he receive another Rh+ blood transfusion, will lead to post-transfusional shock due to agglutination.

2) Rh- mother with Rh+ fetus.During pregnancy,in normal condition blood of mother n fetus wont mix because there is a placental barrier between mother n fetus. but this barrier may increase in permeability during certain conditions (stress, heavy work, running, etc). blood mix can also happen during delivery or miscarriage due to tearing of placenta. this mix wil cause the mother will produce anti-D Rh antibody but the baby will be in normal condition. on her 2nd pregnancy with Rh+ fetus, anti-Rh antibody from mother may pass through placenta & agglutinate & hemolyse fetal blood. the baby will born with hemolytic disease of newborns (HDN) or erythroblastosis fetalis.

notes: about 2% of HDN is due to ABO blood incompability.but this is rare because the size of A & B aglutinogens is bigger, so wont penetrate tru placenta easily.

3) the mother(Rh-) had received blood transfusion from Rh+ donor. the 1st pregnancy maybe effected.

prevention: inject anti-D serum(Rh immune globulin) at 28 to 32 weeks of pregnancy in which the mother is Rh- & father Rh+. this anti-D serum binds fetal erythrocyte antigen so they cant stimulate mother’s immune system.

blood group notation; type of blood according to ABO system plus + or – (indication of Rhesus type)

mine is O+.last friday in physiology class we made experiment to determine blood group.actually the teacher Dr. Efes doesnt want us to use our own blood as experimental object, but using donor’s blood instead. but without her knowing i punctured my own finger with my pin tudung then use my own blood for the experiment (kantoi la..hihi). we tested the blood with serum containing different antibody(serum 0, serum A, n serum B). then in other expriment we tested the blood with anti-Rh..my blood didn’t agglutinate after mixing with all ABO serum but aglutinated when mix with anti-Rh serum. it proved my blood have no agglutinogen A or B but have agglutinogen-D, the characteristic of O blood group with Rh+.

hihi..research dah siap..scara xlangsung i’ve prepared myself for physiology control minggu depan :D

yuuhuu~ 8-)

reference: wikipedia, nobelprize.org, dr. efes class notes, saladin’s basic anat & physio, seniors notes.