2. Erythrocytes

Erythrocytes Overview: 2024-2025

Instructor: Dr. Badegül Sarikaya

• Function: Transport hemoglobin; 3% of hemoglobin leaks into tissue/plasma.

• Carbonic Anhydrase: Enhances CO2 to bicarbonate conversion; hemoglobin buffers pH.

Structure:

• Shape/Size: Biconcave discs, 7.8 micrometers diameter, high surface-area-to-volume ratio.

• Membrane: Composed of lipid bilayer, integral proteins, and membrane skeleton; key proteins include Band-3, glycophorins, and Rh D protein.

Metabolism:

• Lacks nuclei and mitochondria; uses glucose via glycolysis; ATP generated through Embden-Meyerhof pathway.

Fragility:

• Mechanical: Aging increases rigidity.

• Osmotic: Assessed by lysis in hypotonic solutions.

RBC Concentration:

• Normal counts: Men: 5.2 million/mm³; Women: 4.7 million/mm³. Hemoglobin: up to 34 g/100 ml (15 g in men, 14 g in women).

• Indices: Hemoglobin concentration, hematocrit, red cell count, mean cell volume (MCV).

Production:

• Erythropoiesis Locations: Yolk sac (embryo), liver (mid-trimester), bone marrow (postnatal).

• Growth regulated by erythropoietin (EPO); maturation requires B12 and folic acid.

Erythroblastosis Fetalis:

• Rh incompatibility between mother and fetus; prevention via Rh immunoglobulin.

Transfusion Reactions:

• Mismatched blood causes agglutination; blood typing essential beforehand.

• Rh Considerations: Sensitization risks for maternal-fetal health.