Red Cells Prof K Sivapalan ERYTHROCYTE RBC Biconcave

Red Cells Prof. K. Sivapalan

ERYTHROCYTE- RBC • • • Biconcave disc. 7. 2 μ x 2. 2 μ No nucleus. PCV – 45, 35 % Hb% – 14. 5 g/d. L. - Males, – 13. 5 g/d. L. - females • Red cell count – 5, 000 / mm 3. (5 x 106) June 2013 Red Cells 2

Hemoglobin. • • June 2013 4 Units- Heme and peptide. 2 x α chains- 141 AA. 2 x β chains- 146 AA. Molecular weight- 67, 000. Hb A- α 2β 2. Hb A 2 - α 2δ 2. (10 AA differ) Hb F - α 2γ 2. (37 AA differ) Hb S. (sickle cells) Red Cells 3

Heme. • Heme is attached to N terminals in the Peptide Chain. • Oxygenation is loose attachment to iron atom. June 2013 Red Cells 4

Reaction of Heamoglobin. • 1 gram of hemoglobin binds to 1. 34 ml of oxygen. • Hb 4 + 4 O 2 = Hb 4 O 8 (Oxygenation) • Oxyhemoglobin – red color. • Deoxyhemaglobin- blue color - Cyanosis. • Carboxy hemoglobin- cherry red. • Methemoglobin- brown. June 2013 Red Cells 5

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 2013 Red Cells 6

HEMOPOISIS. • Stem cell. • Proerythroblast. – Basophelic. • Early normoblast. • Intermediate normoblast. – Hemoglobin. • Late normoblast. • Reticulocyte. • Erythrocyte. June 2013 Red Cells 7

Hemopoisis. • • Embryo- yalk sack. Later- liver, spleen and lymph nodes. Adultsred 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 2013 Red Cells 8

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 2013 Red Cells 9

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 2013 Red Cells 10

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 2013 Red Cells 11

Investigations on red cell. • Osmotic Fragility. – Two drops of blood in Na. Cl 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 2013 Red Cells 12

Red cell parameters. n n Mean Corpuscular Hemoglobin [MCH] = Hb in g in 100 ml / No. of RBC in 100 ml. = 15/5 x 106 x 105 = 15/5 x 1011 = 30 x 10 -12. = 27 – 32 Pg. Mean Corpuscular Hemoglobin Concentration [MCHC] = Hb in 100 ml / RBC volume in 100 ml. = 15/45 x 100 = 32 – 38 % Mean Corpuscular Volume [MCV] = Volume of RBC in 100 ml / Number of RBC in 100 ml. = 45 / 5 x 1011 = 90 x 10 -12 = 80 – 94 μ 3. Differences between Males and Females. June 2013 Red Cells 13

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. June 2013 Red Cells 14