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WHITE BLOOD CELLS (WBCs)Leukocytes
HMIM BLOCK 224
Lecture - 4DR. ZAHOOR
ObjectivesObjectives
Recognize the different types of WBCs
Write the normal values of the WBCs
Summarize the functions of each WBC
Predict the changes in WBCs in different clinical conditions
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Leukocytes White blood cells or WBCsMobile units of body’s immune defense systemImmune system
Made up of leukocytes, their derivatives, and variety of plasma proteins
Recognizes and destroys or neutralizes materials within body that are foreign to “normal self”
Functions Defends against invading pathogens Identifies and destroys cancer cells that arise in body Functions as a “cleanup crew” that removes worn-out
cells and tissue debris
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LeukocytesColorless – lack hemoglobin WBC can be stained and seen under
microscopeVary in structure, function, and numberSomewhat larger than erythrocytes5 different types of circulating leukocytes
NeutrophilsEosinophilsBasophilsMonocytesLymphocytes
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WBC5 types of Leukocytes can be divided into 1) Granulocytes ( Polymorpho nuclear
granulocytes) 1- Neutrophils 2- Eosinophils 3- Basophils 2) Non- Granulocytes ( Mononuclear
agranulocyte) 4- Monocytes 5- Lymphocytes
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WBC 1- Granulocytes ( Polymorpho nuclear granulocytes)
Polymorpho nuclear granulocytes can be distinguished by looking at their nucleus lobes, and granules present in cytoplasm and on the basis of dye which they take up.
1. Eosinophils – Nucleus bilobed, granules take acidic dye and look red.
2. Basophil – Nucleus segmented, granules take basic dye and look blue.
3. Nuetrophil – Nucleus 2-5 lobes,granules take both acidic and basic dye and look purple or light pink.
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WBC 2. Non- Granulocytes (Mononuclear agranulocyte)
Monocyte and Lymphocyte are called Mononuclear Agranulocyte. Mononuclear (single nucleus), Aganulocytes (cells having no granules)
-Monocyte – is large cell having oval or kidney shape nucleus, No granules in cytoplasm.
-Lymphocyte – has large spherical nucleus that occupies most of the cell , No granules in cytoplasm. 7
GRANULOCYTES AGRANULOCYTES
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Cell ApproximateNormal range(/µL)
Percentage of Total WBC
Total WBC 4000-11000 - - -
Granulocytes
Neutrophils Eosinophils Basophils
3000-6000150-3000-100
60-70%1-4 %
0.25 - 0.5%
Agranulocytes
Lymphocytes1500-4000 20-40%
Monocytes 300-600 2-8%
Concentration (Normal Counts)
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Site of Formation - WBCSite of Formation - WBCUltimately originate from same
undifferentiated multipotent stem cells in red bone marrow
Granulocytes and monocytes are produced only in bone marrow
Lymphocytes are originally produced in bone marrow but most new lymphocytes are actually produced in lymphoid tissues such as lymph nodes and tonsils
Total number of white cells and percentage of each type may vary considerably to meet changing defense needs
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Myeloblast
Erythroblast
Monoblast
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Granulocytes 4-8 hours (1 day)Monocytes 10-20 hours (3 days)Lymphocytes months (100-300 days)
Macrophages Months- years
Life span of leukocytes:
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NEUTROPHILSMost Abundant WBCs 60-70 %
Size: 14-16 µmNucleus: Multilobed 2-5 lobes
Function: Phagocytosis
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DEFENSIVE PROPERTIES OF NEUTROPHILS
1. Diapedesis2. Chemotaxis3. Phagocytosis &
Digestion
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NEUTROPHILS
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Eosinophil Size 12 -14 µm Nucleus – Bilobed Granules contain arginine rich protein, which take
acid dye (eosin) Function: 1. in allergic condition. 2-Phagocytosis Chemotaxis: attracted towards chronic inflammation
Neutralises allergic products such histamine, 5-HT, bradykinin (allergic disease of skin &lungs)
Phagocytosis is same as neutrophil, but less efficient
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Eosinophils count,High eosinophil count:
Parasitic (hook worm, ascaris, bilharzia)Allergic (asthma, rhinitis, drug reaction)Allergic Dermatological diseases
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Basophils Size 12 -14 µm Nucleus – Segmented in center Granules contain polysaccharide granules which take
basic dye methylene blue therefore they look blue in color.
Function
Its granules release heparin, histamine, 5HT.
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MONOCYTESNucleus- single large,kidney shape
Cytoplasm-No Granules but Vacoules
Size: 16-20 µmFunction-Phagocytosis.Life span: 10-20 hours in blood (3 days)
Monocytes Emerge from bone marrow while still
immature and circulate for day or two before settling down in various tissues in body
Mature and enlarge in resident tissue and become known as macrophages (“large eaters”)Life span of Macrophage can range from
several months to yearsBecome professional phagocytes
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TISSUE MACROPHAGE SYSTEM
Examples are: -1. Tissue macrophages in Skin and
Subcutaneous tissues (Histiocytes)2. Macrophages of Lymph Nodes3. Alveolar macrophages4. Tissue macrophages in Liver
sinuses (Kupffer Cells)5. Macrophages of Spleen & Bone
marrow6. Microglia in Brain
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Tissue macrophages in Liver sinuses
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LYMPHOCYTES Nucleus – single, rounded, occupies
most of the cell Cytoplasm - No Granules Size: 10-16 µm Live about 100 to 300 days Function – immunity.-Number increases in viral infection
Lymphocytes Provide immune defense against targets for
which they are specifically programmed2 types of lymphocytes
B lymphocytes Produce antibodies which circulate in blood Responsible for antibody-mediated or humoral immunity
T lymphocytes Do not produce antibodies Directly destroy specific target cells by releasing
chemicals that punch holes in the victim cell (cell-mediated immunity)
Target cells include body cells invaded by viruses and cancer cells
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Lines of DefenseResponse to Inflammation
1st line of defense in Tissue – Tissue macrophages & Physical Barriers
2nd line of defense – Neutrophil Invasion of the inflamed area
3rd line of defense – Monocytes –macrophage invasion of inflamed area
4th line of defense – Increased production of granulocytes and Monocytes by Bone marrow
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IMPORTANT TERMSLeukocytosis – Increase in WBC countLeukopenia - Decrease in WBC countNeutrophilia - Increase in neutrophil
countLeukemias – Abnormal Increase in
immature WBC count (blood cancer).Pus
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Formation of Pus
Dead Neutrophils Dead Macrophages Necrotic tissue
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LEUKEMIALeukemia is cancerous conditionWBC count may be 100,000-500,000/mm3
Most of WBC are immature, therefore, they can not perform normal function of defense
Infections are commonBone marrow produces increase number of
WBC, therefore, there is decrease RBC formation leading to anemia
Decreased platelet formation leading to bleeding
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Thank youThank you
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