Red Cells Prof. K. Sivapalan

June 2013Red Cells2 ERYTHROCYTE- RBC Biconcave disc. 7.2 μ x 2.2 μ No nucleus. PCV – 45, 35 % Hb% - –14.5 g/dL. - Males, –13.5 g/dL. - females Red cell count –5,000,000 / mm 3. (5 x 10 6 )

June 2013Red Cells3 Hemoglobin. 4 Units- Heme and peptide. 2 x α chains- 141 AA. 2 x β chains- 146 AA. Molecular weight- 67,000. Hb A- α 2 β 2. Hb A 2 - α 2 δ 2. (10 AA differ) Hb F - α 2 γ 2. (37 AA differ) Hb S. (sickle cells)

June 2013Red Cells4 Heme. Heme is attached to N terminals in the Peptide Chain. Oxygenation is loose attachment to iron atom.

June 2013Red Cells5 Reaction of Heamoglobin. 1 gram of hemoglobin binds to 1.34 ml of oxygen. Hb O 2 = Hb 4 O 8 (Oxygenation) Oxyhemoglobin – red color. Deoxyhemaglobin- blue color - Cyanosis. Carboxy hemoglobin- cherry red. Methemoglobin- brown.

June 2013Red Cells6 Abnormalities of hemoglobin. Hemoglobinopathies: Mutant genes → abnormal polypeptide chains. Thalassemias: α or β thalassaemia - respective chain is absent or decreased. Defects in regulatory portion of the genes.

June 2013Red Cells7 HEMOPOISIS. Stem cell. Proerythroblast. –Basophelic. Early normoblast. Intermediate normoblast. –Hemoglobin. Late normoblast. Reticulocyte. Erythrocyte.

June 2013Red Cells8 Hemopoisis. Embryo- yalk sack. Later- liver, spleen and lymph nodes. Adults-red bone marrow. Regulation: –Ischemia to kidney tissue → Erythropoitin by Juxta Glomerular Apparatus → increase in hemopoisis. Duration: 4 days. Testesteron stimulates red cell production and result in increased Haemoglobin concentration in adult males. Glucocorticoids also stimulate- polycythaemia in excess secretion.

June 2013Red Cells9 Limitations to Hemopoisis. Protein- severe malnutrition. Iron (Fe): Inclusion in haemoglobin. –Difficulty in absorption. –Food habits. –Loss [females]. Cyanocobalamine (Vit. B 12 ) and, Folic acid: –DNA synthesis.

June 2013Red Cells10 Fate of red cells. Average life span – 120 days [ of the red cells, 1/120 destroyed daily]. Destroyed by the Macropharges in spleen. –[Reticulo - Endothelial System] Trabeculae in spleen – 3 μ. Protein → Amino acid pool. Heam →Iron + Porphyrin. Iron → storage + recycled. Porphyrin → Bilirubin – excreted.

June 2013Red Cells11 Bilirubin Bound to albumin, taken up by the liver. [yellow] Biliverdin – green. Conjugated with glucuronic acid → water soluble and Excreated in bile – green. Intestinal bacteria – stercobilinogen →absorbed – urobilinogen.

June 2013Red Cells12 Investigations on red cell. Osmotic Fragility. –Two drops of blood in NaCl solutions with varying osmolality and observe for hemolysis. Spherocytosis- fragility increased. Hemoglobin concentration. –Talqivist method. –Sahli method (acid haematin formation). –Calorimeters. –Oxygen content. Pack cell volume. –Centrifugation. (buffy coat) Red cell count. –Red cell pipette and hemocytometer.

June 2013Red Cells13 Red cell parameters. Mean Corpuscular Hemoglobin [MCH] Mean Corpuscular Hemoglobin [MCH] = Hb in g in 100 ml / No. of RBC in 100 ml. = 15/5x10 6 x 10 5 = 15/5x10 11 = 30 x = 27 – 32 Pg. Mean Corpuscular Hemoglobin Concentration [MCHC] Mean Corpuscular Hemoglobin Concentration [MCHC] = Hb in 100 ml / RBC volume in 100 ml. = 15/45 x 100 = 32 – 38 % Mean Corpuscular Volume [MCV] Mean Corpuscular Volume [MCV] = Volume of RBC in 100 ml / Number of RBC in 100 ml. = 45 / 5 x = 90 x = 80 – 94 μ 3. Differences between Males and Females. Differences between Males and Females.

June 2013Red Cells14 Anemia. Aplastic anemia: Bone marrow not producing red cells. [normocytic normochromic anaemia] Renal causes- Erythropoitin. Marrow depression: Drugs. Malignancy. [leucaemias] Deficiency anemia: Iron [Microcytic hypochromic anaemia] Vitamin B 12, Folic acid [Macrocytic hyperchromic anaemia, Megaloblastic anaemia.] Hemolytic anemia: malaria, hereditary, drugs.