General Physiology SecolBDSMED102_4.pptx

Second internal examination

1. Course Leader Dr Ambarish E Mail:[email protected] Course Code: BDSMED102 Course Title: General Human Physiology

2. Lecture – 04 RBC Intended Learning Outcome At the end of this lesson student will be able to Recall morphology of RBC Explain the stages of erythropoiesis Describe the factors affecting erythropoiesis

3. Red Blood Cells

4. RBC – Morphology Circular, biconcave, non-nucleated disc 7.2 m diameter. 2.2 m thickness in the periphery. 1.0 m in the centre. Volume - 78-94 m 3 Biconcave disc shape  surface area (140 m 2 ) Alteration in volume, shape  efficiency for diffusion of gases

5. Red Blood Cells Functions O 2 transport CO 2 transport Participate in acid base balance Contribute to the viscosity of the blood Antigens of RBC membrane are useful for identification of blood groups

6. Production of RBC Early few weeks of embryo nucleated RBCs are formed in yolk sac. Middle trimester of gestation mainly in liver & spleen & lymph nodes. Last months RBCs are formed in bone marrow of all bones Bone marrow of flat bone continue to produce RBC into adult life Shaft of long bone stop to produce RBC at puberty while epiphysis continued

7. Haemopoiesis

8. Genesis of RBC / Erythropoiesis All blood cell are formed from Pluripotential hematopoietic stem cells  committed cells: Committed stem cells for RBC Committed stem cells for WBC Growth of different stems cells are controlled by different growth factors

9. Stages of differentiation of RBC Stages of RBC development Committed stem cell Proe rthroblast basophil erythroblast polychromatophil erythroblast orthochromatic erythroblast R eticulocytes Mature erythrocytes Rapid RBC production   reticlocytes in the circulation

10. Erythropoiesis RBC development is characterize by: decrease in cell size disappearance of nucleus appearance of haemoglobin 11

11. Erythropoiesis

12. ERYTHROPOIESIS 15-20µm- basophilic cytoplasm, nucleus with nucleoli. 14-17µm- basophilic cytoplasm, nucleoli disappears. 10-15µm-’ POLYCHROMASIA ’ Hb appears, nucleus condenses. 7-10µm- PYKNOTIC Nucleus Extrusion, Hb is maximum. 7.3µm- Reticulum of basophilic material in the cytoplasm. 7.2µm- Mature red cell with Hb.

13. Proerythroblast

14. Basophilic erythroblast / Early normoblast

15. Polychromatophilic Erythroblast / Intermediate Normoblast

16. Orthochromatic Erythroblast / Late Normoblast

17. Reticulocyte

18. Mature Non - Nucleated Erythrocyte

19. Erythropoiesis : Characteristic features Takes about 7 days to form mature RBC Reduction in cell size Nucleus Size decreases Big nucleus with nucleoli  condensed chromatin  degenerates and disappears Cytoplasm Amount increases Deep basophilic  polychromatophilic  acidophilic Hb appears in intermediate normoblast

20. Factors affecting Erythropoiesis Erythropoietin (EPO): major humoral regulator of erythropoiesis Interleukins, IL3, IL6 & IL1 Dietary: protein, Fe, Cu, Co, Mg, Ca Maturation factors : Vitamin B12 and Folic Acid Vitamin C Castle’s Intrinsic factor for absorption of B12

21. Erythropoeitin Glycoprotein MW - 46000 85-90% formed in endothelial cells of the peritubular capillaries of the renal tubules 10-15% formed in liver, hepatic cells & Kupffer cells Inactivated in liver, excreted in urine

22. Tissue Oxygenation And RBC Formation 23

23. Anaemia Classification: Whitby’s / Etiological Hemorrhagic anaemia Dietary deficiency Aplastic anaemia Hemolytic anaemia Wintrobe’s / Morphological Normocytic Macrocytic Microcytic Pernicious anaemia , Folic acid def anaemia , Iron deficiency anaemia , Spherocytosis

24. Summary Morphology of RBC Haemopoiesis Erythropoiesis Factors affecting erythropoiesis Erythropoietin Anaemia

25. Disclaimer All data and content provided in this presentation are taken from the reference books, internet – websites and links, for informational purposes only.