1. WHITE BLOOD CELLS (WBCs)
Leukocytes
HMIM BLOCK 224
Lecture - 4
DR. ZAHOOR

2. 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

3. 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
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

4. Leukocytes 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

5. 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

6. 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.

7. 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.

8. CLASSIFICATION
GRANULOCYTES
AGRANULOCYTES

10. Percentage of Total WBC
Concentration (Normal Counts)
Cell
Approximate
Normal range
(/µL)
Percentage of Total WBC
Total WBC
- - -
Granulocytes
Neutrophils
Eosinophils
Basophils
0-100
60-70%
1-4 % %
Agranulocytes
Lymphocytes
20-40%
Monocytes
2-8%

11. 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

12. Myeloblast
Erythroblast
Monoblast

13. GENERAL CHARACTERISTICS OF WBCSs

14. Life span of leukocytes:
Granulocytes  4-8 hours (1 day)
Monocytes  hours (3 days)
Lymphocytes  months ( days)
Macrophages Months- years

15. NEUTROPHILS Most Abundant WBCs 60-70 % Size: 14-16 µm
Nucleus: Multilobed 2-5 lobes
Function: Phagocytosis

16. DEFENSIVE PROPERTIES OF NEUTROPHILS
Diapedesis
Chemotaxis
Phagocytosis & Digestion

17. NEUTROPHILS

19. 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

20. Eosinophils count, High eosinophil count:
Parasitic (hook worm, ascaris, bilharzia)
Allergic (asthma, rhinitis, drug reaction)
Allergic Dermatological diseases

21. Basophils
Size 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.

22. MONOCYTES Nucleus- single large,kidney shape
Cytoplasm-No Granules but Vacoules
Size: µm
Function-Phagocytosis.
Life span: hours
in blood (3 days)

23. 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

24. 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

25. Tissue macrophages in Liver sinuses

26. LYMPHOCYTES Nucleus – single, rounded, occupies most of the cell
Cytoplasm - No Granules
Size: µm
Live about 100 to 300 days
Function – immunity.
-Number increases in
viral infection

27. Lymphocytes
Provide immune defense against targets for which they are specifically programmed
2 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

28. 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

29. 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

30. Formation of Pus
Dead Neutrophils
Dead Macrophages
Necrotic tissue

31. LEUKEMIA Leukemia is cancerous condition
WBC count may be 100, ,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

34. Thank you