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White Blood cells

White Blood cells. Most dreaded enemies…….always exposed Multiple defense mechanisms. White blood cells/leukocytes. Mobile units of body’s protective system. Colourless due to lack of haemoglobin so K/a White blood cells Normal count : 4000-11000/cumm of blood (cumm = 1 μ l)

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White Blood cells

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  1. White Blood cells

  2. Most dreaded enemies…….always exposed Multiple defense mechanisms

  3. White blood cells/leukocytes Mobile units of body’s protective system. Colourless due to lack of haemoglobin so K/a White blood cells Normal count : 4000-11000/cumm of blood (cumm = 1μl) Scavengers………..seek out and destroy foreign invader

  4. Five Types • Classified according to the presence or absence of granules and the staining characteristics of their cytoplasm. • Leucocytes appear brightly colored in stained preparations, they have a nuclei and are generally larger in size than RBC’s.

  5. WBC’s Presence of granules Granulocytes Absence of granules Agranulocyte 50-70% 1-4% 0-1% Neutrophils Eosinophils Basophils 2-8% 20-40% Monocytes Lymphocytes Differential leucocyte count : Count expressed in terms of percentage of different types of WBC

  6. Neutrophils • 10-14μm • Stain light purple with neutral dyes • Granules are small and numerous—fine appearance • Several lobes in nucleus (lobes increase with the age of neutrophil) • 65% of WBC count • Highly mobile/very active • Diapedesis—Can leave blood vessels and enter tissue space • Phagocytosis (eater), contain several lysosomes • Lead to inflammatory response • Lifespan : 7hrs in blood, 4-5 days in tissues

  7. Neutrophilia Exercise,Pregnancy Acute infection Tissue destruction Acute stress Neutropenia Hypoplasia of the bone marrow Typhoid fever

  8. Eosinophils • 10-14μm • Large, coarse, numerous granules, stained deep red by eosin • Nuclei with two lobes • 1-4% of WBC count • Half life 1 - 8hrs, then enter tissues (few weeks) • Found in lining of respiratory and digestive tracts • Important functions involve protections against infections caused by parasitic worms and involvement in allergic reactions • Secrete anti-inflammatory substances in allergic reactions

  9. Eosinophilia Infections – parasitic Allergic conditions – asthma, atopic dermatitis, Drug reactions – aspirin, sulphonamides, cephalosporins Neoplasms – leukemia, lymphomas Eosinopenia ACTH Corticosteroids Bone marrow depression

  10. Basophils • 10-14μm • Least numerous - 0.5-1% • Densely packed with large granules, stained purplish black by basic dyes • Contain histamine,serotonin,heparin—inflammatory chemical • Nucleus 2-3 lobed • Lifespan – few hours • Diapedesis—Can leave blood vessels and enter tissue space • Degranulation may protect us from some parasitic infections eg scabies

  11. Basophilia Allergy Tuberculosis Chicken pox leukemia Basopenia Bone Marrow depression After glucocorticoid administration

  12. Monocyte • Largest of WBCs (10-18μm) • Dark kidney/ bean shaped nuclei • Highly phagocytic • Precursors of tissue macrophages • Avg intravascular stay 3 days • In tissues undergo differentiation to form macrophages • Phagocytose foreign particle • Removal of damaged and dying cell debris • Stimulation of granulopoeisis • Interaction with antigen and lymphocytes in immune response

  13. Monocytes and macrophages

  14. Monocytosis Tuberculosis Malaria Leukemia Syphilis Monocytopenia Glucocorticoids Hypoplastic bone marrow

  15. Lymphocyte • Smallest WBC • Large nuclei/small amount of cytoplasm • Show variation in size (small :7-10μm/large: 10-14μm) • Account for 25% of WBC count • Two types—T lymphocytes—attack an infect or cancerous cell, B lymphocytes—produce antibodies against specific antigens (foreign body) • Lifespan highly variable

  16. Lymphocytosis Leukemia Viral infections Lymphocytopenia Hypoplastic marrow ------aplastic anaemia, radiation AIDs

  17. WBC Numbers • Doctors look at WBC numbers. • If number goes up there is some kind of infection and surgery might be needed. • Clinics will count the number of WBC’s in a blood sample, this is called differential count. • A decrease in the number of white blood cells is leukopenia • An increase in the number of white blood cells is leukocytosis.

  18. Formation of WBC’s Formed from pluripotent hematopoetic stem cells By progressive proliferation and differentiation some THSC get commited to form specific leucocyte Bacteria and macrophages stimulate macrophages and monocytes to produce IL-1 and TNF-α which in turn stimulate other cells to produce colony stimulating factors

  19. Regulation of granulopoesis Regulated with great precision in healthy individuals Why is it necessary? Cytokines –proteins released by cells that act as intercellular mediators Growth factors-------------- acting on stem cells immature committed cells specific growth factor

  20. Leukemia Uncontrolled producrion of WBC’s by cancerous mutation of myelogenous or lymphogenous cell Greatly increased number of abnormal WBC’s Undifferentiated WBC’s Two types: lymphocytic and myelogenous Acute/chronic

  21. Spread of cancerous cells to sorrounding bone,spllen, lymph node, liver Development of infection/ bleeding tendency, anemia Rapid deterioration of normal protein tissues of the body. Metabolic starvation Leukemoid reaction

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