Human Blood Groups

Blood Transfusion Reactions and Compatibility

• Vigorous transfusion reactions are most commonly caused by ABO incompatibility.
• Individuals with blood type A can only receive type O blood to avoid severe reactions.
• Universal recipients with blood type AB can accept blood from any other blood type.

Rh Factor and Pregnancy

• An Rh-negative person receiving Rh-positive blood may develop serious immune reactions, including hemolytic transfusion reaction.
• To prevent the buildup of anti-Rh+ antibodies in Rh-negative mothers during pregnancy, Rh immunoglobulin (RhIg) is administered.

Hematopoiesis and Blood Cell Types

• Hematopoiesis, the formation of blood cells, primarily occurs in the bone marrow of adults.
• Red blood cells (RBCs) are anucleate (lack a nucleus) and have a biconcave disc shape.

Leukocyte Functions

• Eosinophils are leukocytes responsible for killing parasitic worms.
• Monocytes are the largest leukocytes, characterized by a distinctive U- or kidney-shaped nucleus.

Blood Components and Their Functions

• Platelets (thrombocytes) are essential for the clotting process in the blood.
• Lymphocytes are involved in reinforcing immunity against specific pathogens.

Regulation of Blood Cell Production

• The rate of Red Blood Cell (RBC) production is controlled by erythropoiesis, which is stimulated by oxygen levels in the blood.
• The kidneys primarily produce erythropoietin, a hormone that regulates RBC production in response to low oxygen levels.

Blood Antigens and Antibodies

• Antigens in the blood determine blood type and can trigger immune responses.
• Antibodies in the blood are proteins that identify and neutralize foreign substances, aiding in the immune response.

Homeostasis of Red Blood Cells

• RBCs maintain homeostasis in response to low blood oxygen levels by increasing production of erythropoietin, stimulating more RBC production to enhance oxygen transport.