Download WHITE BLOOD CELLS (WBCs) Leukocytes

WHITE BLOOD CELLS (WBCs)
Leukocytes
HMIM BLOCK 224
Lecture - 4
DR. ZAHOOR
Objectives
 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 WBCs
 Mobile units of body’s immune defense system
 Immune 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
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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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Leukocytes
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Colorless – lack hemoglobin
WBC can be stained and seen under microscope
Vary in structure, function, and number
Somewhat larger than erythrocytes
5 different types of circulating leukocytes
 Neutrophils
 Eosinophils
 Basophils
 Monocytes
 Lymphocytes
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WBC
 5 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.
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CLASSIFICATION
GRANULOCYTES
AGRANULOCYTES
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Concentration (Normal Counts)
Cell
Approximate
Normal range
(/µL)
Percentage of
Total WBC
Total WBC
Granulocytes
4000-11000
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Neutrophils
Eosinophils
Basophils
Agranulocytes
3000-6000
150-300
0-100
60-70%
1-4 %
0.25 - 0.5%
Lymphocytes
Monocytes
1500-4000
300-600
20-40%
2-8%
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Site of Formation - WBC
 Ultimately 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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GENERAL
CHARACTERISTICS
OF WBCSs
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Life span of leukocytes:
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Granulocytes  4-8 hours (1 day)
Monocytes  10-20 hours (3 days)
Lymphocytes  months (100-300 days)
Macrophages Months- years
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NEUTROPHILS
 Most Abundant
WBCs 60-70 %
 Size: 14-16 µm
 Nucleus:
Multilobed 2-5
lobes
 Function:
Phagocytosis
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DEFENSIVE PROPERTIES OF NEUTROPHILS
1. Diapedesis
2. Chemotaxis
3. 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
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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
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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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MONOCYTES
 Nucleus- single large,kidney shape
 Cytoplasm-No Granules but
Vacoules
 Size: 16-20 µm
 Function-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 years
 Become professional phagocytes
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TISSUE MACROPHAGE SYSTEM
Examples are: 1.
Tissue macrophages in Skin and
Subcutaneous tissues (Histiocytes)
2.
Macrophages of Lymph Nodes
3.
Alveolar macrophages
4.
Tissue macrophages in Liver sinuses
(Kupffer Cells)
5.
Macrophages of Spleen & Bone marrow
6. 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 programmed
 2 types of lymphocytes
 B lymphocytes
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Produce antibodies which circulate in blood
Responsible for antibody-mediated or humoral immunity
 T lymphocytes
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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 Defense
Response 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 TERMS
Leukocytosis – Increase in WBC count
Leukopenia - Decrease in WBC count
Neutrophilia - Increase in neutrophil count
Leukemias – 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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LEUKEMIA
 Leukemia is cancerous condition
 WBC count may be 100,000-500,000/mm3
 Most of WBC are immature, therefore, they can not
perform normal function of defense
 Infections are common
 Bone 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 you
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