2. Granulocytes Granulocytes have irregular-shape nuclei with 2 to 5 lobes. That is why they are called polymorphonuclear leukocytes. The cytoplasm has granules that contain reactive substances that kill microorganisms, and enhance inflammation.

3. Basophlis Have nucleus with two lobes, and grains in the cytoplasm that stain bluish black with basic dye. These are non phagocytic cells that function by releasing histamine, prostaglandins, serotonin and leukotrienes from their granules on proper stimulation (interaction with IgE antibodies).These chemicals released are called vasoactive compounds because they act on blood vessel walls.

4. basophiles

5. Esinophils Have a 2 –lobed nucleus connected by a slender thread of chromatin, and granules stain red acidic dyes. They are important in defence against protozoan and helminthes, parasites by releasing cationic proteins and reactive oxygen metabolites.

6. eosinophiles

7. Neutrophils Stain readily at neutral pH, have with 3 to 5 lobes, and contain primary and secondary granules. The primary granules contain peroxidase, lysozyme and other hydrolytic enzymes, where as the secondary granules have collagenase, lactoferrin and lysozyme,Neutrophiles are highly phagocytic cells.However, unlike macrophages, they do not reside in healthy tissue but aggregate in tissue infected by pathogens.

8. Neutrophils

9. Dendritic cells Dendritic cells can recognize pathogens by their specific molecular patterns and can differentiate between “self molecules” potentially pathogenic foreign molecules. These are antigen –presenting cells(for t helper cells) >they have long membrane extension resembling the dendrites of the neurons. These cells are found in node, spleen and thymus, skin(langerhans cells) and other tissues.

10. Mast cells Mast cells are also derived from the bone marrow, they are found in the connective tissue. They contain granules with histamine. Mast cells along with basophiles are important in the development of allergies and hypersensititives.

11. Staining Giemsa stain is used.It is mixure of methylene blue and eosin. Make it 1:10 dilution or with (pH -6.8-7.2) To stain a smear, take a slide with a fixed and dry smear.Put on the slide a drop of stain until it is fully covered. Stain for about 16 min. Rinse the slide distilled water at room temp. Drain off the water and leave the slide to dry. Then observe under microscope for different types of cells.

12. % of cells in the blood Neutrophils 50 – 70% Eosinophil 2 – 4 % Basophil 0, 5- 1% Lymphocyte 20- 40% Monocyte 3 – 8%