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By the end of this section, you will be able to:
  • Describe the two basic physiological consequences of transfusion of incompatible blood
  • Compare and contrast ABO and Rh blood groups
  • Identify which blood groups may be safely transfused into patients with different ABO types
  • Discuss the pathophysiology of hemolytic disease of the newborn

Blood transfusions in humans were risky procedures until the discovery of the major human blood groups by Karl Landsteiner, an Austrian biologist and physician, in 1900. Until that point, physicians did not understand that death sometimes followed blood transfusions, when the type of donor blood infused into the patient was incompatible with the patient’s own blood. Blood groups are determined by the presence or absence of specific marker molecules on the plasma membranes of erythrocytes. With their discovery, it became possible for the first time to match patient-donor blood types and prevent transfusion reactions and deaths.

Antigens, antibodies, and transfusion reactions

Antigens are substances that the body does not recognize as belonging to the “self” and that therefore trigger a defensive response from the leukocytes of the immune system. (Seek more content for additional information on immunity.) Here, we will focus on the role of immunity in blood transfusion reactions. With RBCs in particular, you may see the antigens referred to as isoantigens or agglutinogens (surface antigens) and the antibodies referred to as isoantibodies or agglutinins. In this chapter, we will use the more common terms antigens and antibodies.

Antigens are generally large proteins, but may include other classes of organic molecules, including carbohydrates, lipids, and nucleic acids. Following an infusion of incompatible blood, erythrocytes with foreign antigens appear in the bloodstream and trigger an immune response. Proteins called antibodies (immunoglobulins), which are produced by certain B lymphocytes called plasma cells, attach to the antigens on the plasma membranes of the infused erythrocytes and cause them to adhere to one another.

  • Because the arms of the Y-shaped antibodies attach randomly to more than one nonself erythrocyte surface, they form clumps of erythrocytes. This process is called agglutination    .
  • The clumps of erythrocytes block small blood vessels throughout the body, depriving tissues of oxygen and nutrients.
  • As the erythrocyte clumps are degraded, in a process called hemolysis    , their hemoglobin is released into the bloodstream. This hemoglobin travels to the kidneys, which are responsible for filtration of the blood. However, the load of hemoglobin released can easily overwhelm the kidney’s capacity to clear it, and the patient can quickly develop kidney failure.

More than 50 antigens have been identified on erythrocyte membranes, but the most significant in terms of their potential harm to patients are classified in two groups: the ABO blood group and the Rh blood group.

The abo blood group

Although the ABO blood group    name consists of three letters, ABO blood typing designates the presence or absence of just two antigens, A and B. Both are glycoproteins. People whose erythrocytes have A antigens on their erythrocyte membrane surfaces are designated blood type A, and those whose erythrocytes have B antigens are blood type B. People can also have both A and B antigens on their erythrocytes, in which case they are blood type AB. People with neither A nor B antigens are designated blood type O. ABO blood types are genetically determined.

Questions & Answers

what are data colletion method in community diagnodis
loice Reply
50 prefix and surfix
Martha Reply
why arteries deeper than veins?!
Cismaan Reply
arteries colour of blood is deeper than that of vein because its blood contains oxygen which is adhered to haemoglobin(a protein which gives the blood its red color) , while vein contains deoxygenated blood(blood without oxygen)
As we know, vein carries used blood to the heart. when we say used blood, we mean to say, blood that its content(oxygen and other nutrients) has been used up.
Arteries are deeper b'cuz they need to be protected.......If they are ruptured they cannot form clot and repair themselves.... Moreover, the pressure of blood is too high for the artery to form the clot and repair itself....... Hence, Arteries are deeper than veins........
Than u all. Special thanks too AMEL JEELANI.
You're welcome......
Thanks all
describe the location of the macula densa and explain its role in the regulation of renin secretion and in tubuglomerular feedback
mwamba Reply
its located near the vascular pole of the glomurelus also regulate blood pressure and the filtration rate of glomurelus
what are the three methods of data collection used during a community diagnosis
Interviews. Questionnaires and Surveys. Observations.
Describe two early induced responses and what pathogens they affect
olivia Reply
what are pathogens
pathogens are disease-causing agents/organisms
pathogen are the causative of disease
thank you sister
What are organelles
The are little organs found in cells of living things... Eg gogi apparatus
what is anatomy
Linda Reply
is the study of the structures of the body and how they relates to each other
Anatomy is the study of the structures of body parts and how they relates to each other
is the study of the structure of the body and how they relates to each other
what are the difference between Pacinian corpuscle and cutaneous vascular plexus?
thivya Reply
what are membranous epithelial tissues
Naa Reply
they are the lining and covering epithelial tissues which cover body surfaces and line cavities... they're grouped into simple and stratified according to the number of layers and squamous, cuboidal and columnar according to their shape
what is an acina
acina is known to be the basic functional unit of the lungs .(singular:- acinus) this is where the alveoli(the gaseous exchange site) is found...
what happens to the unfertilized egg
the study of tissues is called
Scandy Reply
microscopic or histology anatomy
What specific types of biological macromolecules do living things require and why?
Marieland Reply
what is partial pressure?
Tariq Reply
it is the pressure exerted by mixture of gases...
What is the Important of studying anatomy and philosophy
Michael Reply
because to know the mechanisms of our body
to discover the regional structural of human body based on physically and also biochemically.
how many region do we have in human body
nsofor Reply
head thorax abdomen and many kind of...
what is principal ponatine nucleas
Human body can be divided into different regions on the basis of: 1. Systems: e.g. digestive system, respiratory system, excretory system etc.. 2. Parts: e.g. head, thorax, neck, upper limbs, lower limbs etc..
we have 9 region in d human body
what is systematic anatomy?
nsofor Reply
it is the anatomy or study of a certain body system for example the digestive system. or respiratory system.
It is a group of structure that work together to perform a unique function..

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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