Stages of Development of Blood Cells

1. Stages of Development of Blood Cells Dr. Sama ulHaque Dr Rania Gabr

2. Objectives • Understand the composition of whole blood. • How to prepare a blood smear. • Describe the structure of Erythrocyte. • Enlist different types of leucocytes. • Explain the differentiation of myeloid and lymphoid stem cells. • Discuss the development of blood cells in red bone marrow.

3. Composition of Whole Blood

4. Preparing a Blood Smear

5. Formed elements Red Blood cells Platelets White blood cells Granulocytes (Polymorphonucleated) Agranuloctes (Mononucleated) Neutrophils Basophils Lymphocytes Monocytes Eosinophils

6. Blood Cells

7. Blood Cells

8. ERYTHROCYTE • These cells are: • biconcave disk •no nucleus •~7.8 μmdiameter fresh; • 7.2 -7.4 in stained smears •contains hemoglobin The primary function of these cells is to carry oxygen from the lungs to the body cells. Normally: (4-6 million )erythrocytes per cubic millimeter of blood,

9. Erythrocyte

10. Normal Human Erythrocyte

11. Diameters greater than 9 um are called: “MACROCTES” Diameters less than 6 um are called: “ MICROCYTES” Sickle cell anemia is an inherited condition which results in some erythrocytes being malformed. The gene for this condition causes the hemoglobin to be incorrectly formed, which in turn causes some erythrocytes to take on a crescent shape. These cells are not able to carry adequate amounts of oxygen to cells.

12. Leukocytes (6-10,000 per μL) Granulocytes (polymorphonuclear leukocytes): –Neutrophils -60-70% –Eosinophils -2-4% –Basophils -0.5-1% •Agranulocytes (mononuclear leukocytes) –Lymphocytes -20-30% –Monocytes -3-8%

13. Types of Human LeucocytesNeutrophils, eosinophils, and basophils have granules that stain specifically with certain dyes and are called granulocytes. Lymphocytes and monocytes are considered agranulocytes, even though they may show azurophilic granules (lysosomes), which are also present in other leukocytes.

14. NeutrophilsNeutrophils can be identified by their multilobulated nuclei, with lobules held together by thin strands. With this feature the cells are often called polymorphonuclear leukocytes, or just polymorphs. These cells are capable of phagocytizing foreign cells, toxins, and viruses.

15. When taking a Differential WBC Count of normal blood, this type of cell would be the most numerous. Normally, neutrophils account for 60-70% of all leukocytes. If the count exceeds this amount(Neutrophilia), the cause is usually due to an acute infection such as appendicitis, smallpox or rheumatic fever. If the count is considerably less(Neutropenia), it may be due to a viral infection such as influenza, hepatitis, or rubella.

16. EosinophilsEosinophils are about the same size as neutrophils but have bilobed nuclei and abundant coarse cytoplasmic granules. The cytoplasm is often filled with brightly eosinophilic specific granules, but also includes some azurophilic granules. (a):A eosinophil next to a neutrophil for comparison with its nucleus and granules. (b): Even with granules filling the cytoplasm, the two nuclear lobes of eosinophils are usually clear. (Does it look like a telephone receiver?)

17. Function: 1- The granules contain digestive enzymes that are particularly effective against parasitic worms in their larval form. 2- These cells also phagocytize (antigen - antibody complexes). These cells account for less than 5% of the WBC's. Increases beyond this amount(Eosinopilia): may be due to parasitic diseases, bronchial asthma or hay fever. Eosinopeniamay occur when the body is severely stressed.

18. BasophilsApproximately the same size as neutrophils and eosinophils, but have large, strongly basophilic specific granules which usually obstruct the appearance of the nucleus having two or three irregular lobes. These granules contain histamines (cause vasodilation) and heparin(anticoagulant).

19. Lymphocytes Lymphocytes are agranulocytes and lack the specific granules characteristic of granulocytes. (a):Small lymphocytes are slightly larger than the neighboring erythrocytes with spherical nucleus. (b): Medium lymphocytes are distinctly larger than erythrocytes. (c): Large lymphocytes, much larger than erythrocytes. Round, dark, heterochromatic nucleus –like an “ink spot“ These cells play an important role in our immune response.

20. MonocytesMonocytes are large agranulocytes that circulate as precursors to macrophages and other cells of the mononuclear phagocyte system. Monocytes show their eccentric nuclei indented, kidney shaped, or U shaped. The largest leucocyte.

21. PlateletsPlatelets are cell fragments 2–4 µm in diameter derived from megakaryocytes of bone marrow. Their primary function is to rapidly release the content of their granules upon contact with collagen to begin the process of clot formation and reduce blood loss from the vasculature. Platelets (arrows) are often found as aggregates.

22. Summary of Formed Elements

24. Differentiation of Myeloid And Lymphoid Stem Cells 1. EPO– Erythropoietin 2. CSF– Colony Stimulating Factor 3. GM-CSF– Granulocyte+Macrophage CSF 4. M-CSF– Macrophage CSF 5. G-CSF– Granulocyte CSF

26. Differentiation of Myeloid And Lymphoid Stem Cells

27. Development of Blood Cells in Red Bone Marrow

28. Thank You