bone marrow & erythropoiesis histology.pptx

bone marrow & erythropoiesis

1. Hemopoiesis BY: Nada Essam & Hany Elsied

2. Table of contents 01 02 03 Hematopoietic tissues Bone marrow Erythropoiesis

3. What is Hemopoiesis ? Hemopoiesis means: the production of all blood cells. Erythropoiesis : erythrocytes (RBCs) Leukopoiesis : leukocytes (WBCs) Thrombopoiesis : thrombocytes (platelets)

4. Hematopoietic tissues 01

5. Hemopoietic tissues Hemopoietic tissues : the sites where new blood cells are formed. It includes: The yolk sac (Yolk sac phase) : in the 2nd week of gestation Liver (hepatic phase) : 8 weeks until 6 – 7 months of fetal life Bone marrow (bone marrow phase) : from the 2nd trimester

6. Bone Marrow 02

7. Bone marrow Bone marrow (BM) is the major location for hematopoiesis. Types of bone marrow : Red BM Yellow BM Color red due to its high content of HB yellow due to its high content of fat cells Site In fetus: most of the marrow In adults: present in epiphyses of long bones, Flat bones. Most of marrow in adults Function - Production of blood cells - Destruction of old RBCs. - Storage of fats, - In time of need, it can change into active red type. Red BM Yellow BM

8. Bone marrow Structure Stroma Parenchyma Modified fibroblasts (reticular cells): produce reticular fibers Reticular fibers supporting hemopoietic cells. Macrophages. Sinusoids: Thin-walled vessels Form network. Sinusoidal wall consists of 1.fenestrated endothelial cells 2.discontinuous basal lamina 3.outer adventitial cell layer. Hemopoietic cords: Contain 1. megakaryocytes 2.developing blood cells 3.macrophages 4.mast cells 5.some adipose cells. 1 2

9. Erythropoiesis 03

10. Erythropoiesis (duration : 21 days) Pluripotential stem cell (PPSC) Multipotential Myloid stem cell (CFU-M) Proerythroblast Basophilic erythroblast Polychromatophilic erythroblast Orthchromatophilic erythroblast (Normoblast) Polychromatophilic erythrocyte (Reticulocyte ) Erythrocyte (mature RBC)

11. Erythropoiesis Size: 12-15 Μ M Cytoplasm: mildly basophilic (ribosomes). Nucleus: large, spherical with 1-2 nucleoli. Size: 14 μ m Cytoplasm: deeply basophilic (ribosomes). Nucleus: smaller, more heterochromatic nucleus. No nucleoli seen. 1. Proerythroblast 2. Basophilic erythroblast 3. Polychromatophilic erythroblast Last cell can be divide Hemoglobin production begins. Size: 11 μ m Cytoplasm: polychromatophilic (blue & red color). Nucleus : small & deeply stained.

12. Erythropoiesis Size: 8 μ m Cytoplasm: acidophilic (due to Hb ). Nucleus: small, deeply stained extruded nucleus is phagocytosed by macrophages. Immature RBCs. Size: slightly larger than RBCs. Cytoplasm: still retains some polyribosomes (spots/threads) No Nucleus ˂1.5% of the total RBCs (Brilliant cresyl blue stain ). 4. Orthochromatophilic erythroblast 5. Reticulocytes 6. Erythrocytes Mature RBCs (biconcave discs.) Size: 7.5 μ m. Cytoplasm: full of Hb (acidophilic). Life span: 120 days.

13. This treatment is 10 times faster than previous treatments 50% Reduction in complications 10x faster 85% Success rate for the breakthrough

14. Thank You