Why do blood types matter? - Natalie S. Hodge
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The different types of blood and their significance in the immune system.
Blood Types and Antigens
- Our blood comes in different varieties due to the presence of antigens on red blood cells' membrane. These antigens communicate with white blood cells, which protect against infection. Antigens serve as identifying markers for the immune system to recognize our body's own cells without attacking them as foreign bodies. The two main kinds of antigens, A and B, determine our blood type.
- Red blood cells have a protein called hemoglobin that binds to oxygen, allowing them to transport it throughout the body.
- A and B antigens are coded for by three different alleles: A allele codes for A antigen, B allele codes for B antigen, and O allele codes for neither antigen.
- Dominance determines the expression of alleles: A and B alleles are dominant while O is recessive.
Inheritance and Blood Types
- Each individual inherits two alleles determining their blood type from each parent. When these alleles are different, one overrides the other based on dominance.
- Different combinations of alleles result in different blood types: AA or AO gives type A, BB or BO gives type B, AB gives type AB, OO gives type O.
- Individuals with two O alleles produce blood cells without A or B antigens.
Importance of Blood Types
- Blood types matter for transfusions as using an incompatible blood type can lead to severe complications or even death.
- Type A individuals should receive type A or O blood; Type B individuals should receive type B or O blood; Type AB individuals can receive any blood type; Type O individuals should receive type O blood.
- Type AB individuals are universal recipients as they don't produce antibodies against A or B antigens. Type O individuals are universal donors but produce antibodies that reject any other blood type.
Rh Factor and Pregnancy
- The Rh factor, referring to the presence or absence of the D antigen, can complicate transfusions and cause issues in pregnancy.
- An Rh- mother carrying an Rh+ child may produce Rh antibodies that attack the fetus, leading to hemolytic disease of the newborn.
Blood Types in Different Species
- Different species have different sets of antigens, including blood types.
- Humans share four main blood types with apes.
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