Blood groups are classified based on the presence or absence of specific antigens on the surface of red blood cells and antibodies in the plasma. The two most important systems used worldwide are the ABO system and the Rh system, but there are many others recognized for clinical and scientific purpoRead more
Blood groups are classified based on the presence or absence of specific antigens on the surface of red blood cells and antibodies in the plasma. The two most important systems used worldwide are the ABO system and the Rh system, but there are many others recognized for clinical and scientific purposes.
🩸 Major Blood Group Systems
1. ABO Blood Group System
– A: Has A antigens on red cells and anti-B antibodies in plasma.
– B: Has B antigens and anti-A antibodies.
– AB: Has both A and B antigens, no antibodies.
– O: Has no antigens, but both anti-A and anti-B antibodies.
– Most critical for transfusions and organ transplants.
2. Rh (Rhesus) Blood Group System
– Rh Positive (Rh⁺): Has the RhD antigen.
– Rh Negative (Rh⁻): Lacks the RhD antigen.
– Important in pregnancy and transfusion compatibility.
🧬 Other Recognized Blood Group Systems
The International Society of Blood Transfusion (ISBT) recognizes 43 blood group systems, including:
1. MNS- M, N, S, s, U (Involved in transfusion reactions)
2. Kell- K, k (Can cause hemolytic disease of the newborn)
3. Duffy- Fya, Fyb (Associated with malaria resistance)
4. Kidd- Jka, Jkb- Important in delayed transfusion reactions)
5. Lutheran- Lua, Lub (Rarely causes transfusion issues)
6. Lewis- Lea, Leb (Found in secretions and plasma)
7. P- P1, Pk (Linked to rare hemolytic reactions)
Here's a short overview of the synthesis of hemoglobin, the oxygen-carrying protein found in red blood cells: 🧬 Hemoglobin Synthesis: A Two-Part Process 1. Heme Synthesis - Occurs in the mitochondria and cytosol of developing red blood cells. - Begins with glycine + succinyl-CoA, forming δ-aminolevuRead more
Here’s a short overview of the synthesis of hemoglobin, the oxygen-carrying protein found in red blood cells:
🧬 Hemoglobin Synthesis: A Two-Part Process
1. Heme Synthesis
– Occurs in the mitochondria and cytosol of developing red blood cells.
– Begins with glycine + succinyl-CoA, forming δ-aminolevulinic acid (ALA).
– ALA undergoes several steps to form protoporphyrin IX.
– Iron (Fe²⁺) is inserted into protoporphyrin IX by the enzyme ferrochelatase, forming heme.
2. Globin Chain Synthesis
– Takes place in ribosomes of red blood cell precursors.
– DNA is transcribed into mRNA, which is translated into globin polypeptides.
– Different globin genes produce alpha, beta, gamma, or delta chains depending on developmental stage.
– Two alpha and two non-alpha chains (e.g., beta) combine with four heme groups to form functional hemoglobin (HbA).
🧪 Final Assembly
See less– Heme and globin chains combine in the cytoplasm to form hemoglobin tetramers.
– Each hemoglobin molecule can carry four oxygen molecules.