Exam 1 Review:  Chapter 17:  Blood Typing

blood type = blood group - Any of several immunologically distinct, genetically determined classes of human blood which are based on the presence or absence of certain erythrocyte surface antigens (glycoproteins) and are clinically identified by characteristic agglutination reactions; for blood transfusion purposes, the ABO and Rh blood group systems are the most important.

agglutinogen - An erythrocyte (RBC) surface antigen (immunologically distinct, genetically determined glycoproteins) which may stimulate the production of a particular specific agglutinin (antibody) in individuals lacking that particular agglutinogen (antigen); e.g., the antigens involved in the ABO and Rh blood group systems.

agglutinin - A molecule, such as an antibody, which is capable of causing agglutination (clumping) of a particular antigen, especially red blood cells or bacteria.

agglutination - The clumping together of red blood cells, or bacteria, or other particulate/cellular antigens, usually in response to a specific antibody.

ABO system - A classification system for human blood which identifies four major blood types/groups based on the presence or absence of two antigens (agglutinogens), A and B substances (glycoproteins), determined by specific genetic alleles, on red blood cell membranes; the four blood types/groups (A, B, AB, and O, in which O designates blood that lacks both antigens) are important in determining the compatibility of blood for transfusion.

Rh system - A classification system for human blood which identifies two major blood types/groups based on the presence or absence of one antigen (agglutinogen), Rh substance = D antigen (glycoprotein), determined by specific genetic alleles, on red blood cell membranes; the two blood types/groups (Rh positive and Rh negative, in which Rh^- designates blood that lacks the D antigen) are important in determining the compatibility of blood for transfusion.

autologous transfusions - A transfer of whole blood or blood products in which the blood, blood component, or bone marrow is derived from and then transferred to the same individual's body (donor = recipient).

hemolysis - The destruction or dissolution of red blood cells by destruction of the outer cell membrane, with subsequent release of hemoglobin; it may be caused by bacterial hemolysins, antibodies, the complement proteins of the blood, by hypotonic solutions, by defects in the red blood cell membrane, or by certain chemicals.

hemolytic disease of the newborn = erythroblastosis fetalis - A severe hemolytic disease of a fetus or newborn infant caused by the production of maternal antibodies (usually anti-D) against the fetal red blood cells, usually involving Rh incompatibility between the mother (who must be Rh^- and the fetus who must be Rh⁺⁾.

List:

9. The four different blood types occurring in the ABO blood group system and the naturally occurring antibodies (agglutinins) associated with each of
     the four blood types.

Describe:

6. The ABO blood type system and how it works.

The ABO blood type system is a classification system for human blood which identifies four major blood types/groups based on the presence or absence of two antigens (agglutinogens), A and B substances (glycoproteins), on red blood cell membranes; the four blood types/groups (A, B, AB, and O, in which O designates blood that lacks both antigens) are important in determining the compatibility of blood for transfusion. 

The presence of A and B substances on red blood cells is determined by the presence of specific alleles inherited from one's parents.  Since the alleles show co-dominance, a person who receives neither the A or the B allele will be Type O; a person who receives only the A allele will be Type A; a person who receives only the B allele will be Type B; and a person who receives a copy of both the A and the B allele will be Type AB. 

Because the immunogenic portions of A and B substances are merely two simple sugar side chains which happen to be quite common in nature in other molecules (e.g., in dusts, pollens, mold spores, plant matter, etc.), most individuals are repeatedly exposed to A and B substances from their environment.  Those human individuals who do not manufacture their own A or B substance recognize it as a foreign material to which their immune systems responds.  This is the reason individuals develop naturally occurring antibodies complementary (aglutinins) to one or both substances, if they lack them on their red blood cells.  [See table above.]