Blood cells and hematopoesis

blood cells formation

1. BLOOD CELLS AND HEMATOPOESIS presented by MISS TASMIA ZEB

2. COMPONENT OF THE BLOOD Blood is specialized connective tissue Composed by : Formed elements Fluid component , Plasma (the extracellular(matrix)

3. FORMED ELEMENTS OF BLOOD Formed elements : cells and cell fragments ( platelets ) The cells of blood : red blood cells (RBC) white blood cells (WBCs, leukocytes).

4. Haemopoiesis: Stages in the development of blood cells

5. HEMATOPOIESIS Mature blood cells have a relatively short life span Must be continusly replaced by stem cells Stem cells produce in HEMATOPOIETIC ORGAN

6. short definitions Haematopoiesis is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. Erythropoiesis is the process which produces red blood cells. which is the development from erythropoietic stem cell to mature red blood cell. Leukopoiesis is a form of hematopoiesis in which white blood cells (WBC, or leukocytes) are formed in bone marrow located in bones in adults hematopoietic organs in the fetus. Granulopoiesis is the process by which committed hematopoietic progenitor cells develop into granulocytes under the influence of various growth factors and cytokines. Thrombopoesis Platelets are produced from very large bone marrow cells called megakaryocytes. As megakaryocytes develop into giant cells, they undergo a process of fragmentation that results in the release of over 1,000 platelets per megakaryocyte.

7. Hematopoietic stem cells An immature cell that can develop into all types of blood cells, including white blood cells, red blood cells, and platelets. Hematopoietic stem cells are found in the peripheral blood and the bone marrow. Also called blood stem cell. Multi-potency is the ability to differentiate into all functional blood cells. Self-renewal is the ability to give rise to Hematopoetic stem cell itself without differentiation. Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent. Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.

8. HEMA TOPOIESIS ERYTHROPOESIS: Formation of the erythrocytes (RBCs red blood cells) LEUKOPOESIS: Formation of the white blood cells GRANULOPOESIS: Formation of the granulocytes (neuthrophil, eosinophil, and basophil THROMBOPOESIS: Formation of the platelets

9. Hematopoesis loation Hematopoesis occour in primary and secondary organs: primary organs include:Bone marrow and thymus secondary organs include:spleen,lymphatic system and tonsils THYMUS: Glandular lymphatic organ near the heart where T lymphocytes mature well developed at birth and increase in size until puberty when it starts to decrease in size.

10. PRENATAL HEMOPOIESIS Subdivide into four phases : Mesoblastic : begin after 2 weeks after conception at yolk sac Mesenchymal cells aggregate into blood islands Hepatic Begins at 6 weeks until end of gestation Nucleated erythrocyte Appear of leucocyte (8th week) Splenic Begin at second trimester until end of gestation Myeloid Begin at the end of second trimester Hemopoiesis at bone marrow

11. POSTNATAL HEMOPOIESIS Hemopoiesis almost exclusively in BONE MARROW Stem cells undergo multiple cells divisions and differentiation Replace the cells that leave the blood stream, die or destroy

12. Haematopoiesis during foetal life and infancy Blood cell production begins at 14–20 days in the foetal sac and this is the site of haematopoiesis for about 2 months. The liver and spleen become the main sites of blood cell production during the second trimester of pregnancy and foetal bone marrow in the third trimester. At birth, haematopoiesis is confined to the bone marrow. During infancy and up to about 4 years of age, almost all the bones of the body contain blood cell producing red marrow. Haematopoiesis during adult life By about 25 years of age, the main sites of haematopoiesis are the vertebrae, ribs, sternum, skull bones, pelvis and sacrum, and the proximal ends of the femur and humerus. At these sites about half the marrow is red active cell producing marrow and the remainder, non-cell producing yellow fatty marrow. Other bone marrow cavities in the body contain nonhaematopoietic fatty marrow. In certain blood disorders, e.g. chronic dyserythropoietic and haemolytic anaemias and myelofibrosis, blood cell production can resume in the liver and spleen (extramedullary haematopoiesis) and the fatty marrow in some bones can become replaced by haematopoietic marrow.

13. HEMOPOIETIC GROWTH FACTORS Table 10-6 Gartner colour text histology Regulated the hemopoiesis Produce by spesific cells Acts on spesific stem cells, progenitor cells, and precursor cells The route to deliver growth factor : Via blood stream Secrete near the hemopoietic cells Direct cell-cell contact Induced rapid mitosis or and differentiation Most ot them are glycoproteins

14. ERYTHROCYTE Biconcave-shape disk Without nuclei and organelles Have soluble enzymes Filled with Hemoglobin (Hb) Average life span of erythrocyte : 120 days

15. GRANULOCYTOPOIESIS

16. NEUTROPHILS 60-70% of total leucocytes 9-12 µm in diameter Multilobe nucleus Female : drum stick/Barr Body Granules : Small spesific granules Azurophilic granules (Lysosomes) Tertiary granules (gelatine and cathepsins) Function : Phagocytes

17. EOSINOPHILS 4% of total leucocyte 10 - 14 µm in diameter Bilobed nucleus Many large spesific granules stained by eosin Function : Eliminate antibody- antigen complexes Destroy parasitic worms

18. B ASO P HILS <1% of total leucocyte 8-10 µm in diameter S-shape nucleus (irregular lobes) Large spesific granules obscured the nucleus Granules (dark blue) contain heparin & histamin Surface receptor (Ig E receptors) Function : As initiator of inflamatory process

19. BONE MARROW A gelatinous, vascular connective tissue located in medulary cavity of long bones Responsible for hemopoiesis Structure : Vascular compartment Extensive network of sinusoids , arteries and veins form the Hemopoietic compartment Islands of hematopoietic cells Hemopoietic cells in various stage of maturation

20. LYMPHOCYTES 20%-25% of total leucocyte 8-10 µm in diameter Round nucleus with slight indented, occupies most of the cell Contain few azurophilic granules

21. MONOCYTES Largest circulating blood cells 3-8% ot total leucocyte Large, acentric, kidney- shape nucleus numerous azurophlic granules Migrate to the connective tissue  MACROPHAGES (phagocytose antigens and as APC)

22. RED VS YELLOW BONE MARROW

23. PLATELET FORMATION CFU-Meg, gives rise the Megakaryoblast Megakaryoblast differentiate  Megakaryocytes (single lobulated nucleus) Megakaryocytes protrude  clusters of proplatelets  platelets

24. PL A TELETS 250.000-400.000 platelets/mm3 2 to 4 µm in diameter Display peripheral clear region (hyalomere ) and central darker region (granulomere) receptor molecules (glycocalyx) on plasmalemma Function : Blood clott

25. LEARNING TASKS Expain the composition of the blood! Explain the structure of formed elements of blood! How to differentiate the blood cells from a blood-smear? Explain the classification and function of leucocyte ! Explain the maturation of lymphocyte! What blood cell would be in abundance during an active parasitic infection? Explain your answer! Eplain the structure and function of platelets! What blood cell in bone marrow is the earliest recognizable stage of the red blood cell line? Describe the structure of erythrocyte if lack of this nutrient: vitamin B12 and iron during the erythrocytopoiesis