Final answer:
Blood type refers to the specific antigens present on the surface of erythrocytes, which are key for blood transfusions and are determined by the ABO and Rhesus (Rh) blood group systems.
Step-by-step explanation:
Blood type refers to the kind of antigens found on the surface of erythrocytes (red blood cells). Specifically, blood type is a genetic characteristic related to the presence or absence of certain molecules known as antigens on erythrocyte membranes. These antigens are critical for blood transfusions as they must be compatible between the donor and recipient to avoid adverse reactions.
The ABO blood group system categorizes the presence or absence of two antigens: A and B. People with type A blood have A antigens, those with type B blood have B antigens, those with type AB blood have both, and those with type O blood have neither antigen. Another significant antigen is the Rh factor, determining if the blood type is positive or negative. Thus, when referencing someone's full blood type, it often includes both the ABO group and the Rh factor, such as A+ or O-.
Understanding blood types is crucial for safe blood transfusions, organ transplants, and understanding possible inheritance patterns in families for this trait. The surface antigens in the ABO blood system are glycolipids and responsible for reactions with antibodies in the plasma when incompatible blood types are mixed.