1. White Blood Cells (WBC's) or Leukocytes

2. .
Classification of WBC's:
Granulocytes (polymorphonuclear leukocytes): cytoplasm contains granules. This type is the most numerous which is subdivided into: A.Neutrophils.
B. Eosinophils.
C.Basophiles.
2. Agranulocytes(Mononuclear leukocytes): have agranular cytoplasm (no granules) and subdivided into:
a.Lymphocytes b. Monocytes.

9. WBC count in the blood
Total WBC count: normally is WBC/c.mm of human blood in both male and female.
b. Differential WBC's count which indicates the percentage (%) of each type of leukocytes in the blood:
Neutrophils: 60-70%
Eosinophils: 1- 4%
Basophiles: 0.5-1%
Monocytes: 2- 8%
Lymphocytes: %

10. 2. Leukopoiesis: production of WBCs.
a. Myeloblasts: from which granulocytes (neutrophils,eosinophils and basophiles).
b. Lymphoblasts: from which lymphocytes
developed.
c. Monoblasts: from which monocyte developed .
D.Megakaryoblast:fromwhich megakaryocytes developed ended in the formation of platelets.

12. Genesis of WBCs
The granulocytes & monocytes are formed in the bone marrow
Lymphocytes & Plasma cells are formed partially in the bone marrow & mainly in the lymphogenous tissues,spleen,thymus, tonsils .
WBCs stored in the bone marrow(BM) until needed, their number in the BM is about 3 times as many as circulating WBC in the blood.In(BM)MYELOID:ERYTHROID ratio= 3:1
Lymphocytes are stored in the lymphoid tissues.

13. Life span of the WBCs
Normally granulocytes after being released from BM are 4-8 hours in the blood & another 4-5 days in tissues in serious infections their life span become shorter .
Monocytes hours in the blood when become macrophages they live for months
Lymphocytes life span is weeks to months or years.
Platelets life span is 10 days normally .

14. 3. Most leukocytes are mobile, exhibiting:
1- ameboid movement: Both neutrophils and macrophages can move through tissues.
2- diapedesis : Neutrophils and macrophages squeeze through the pores of the blood capillaries by diapedesis.
3-chemotaxis:Attraction of WBCs to inflamed tissue areas , the chemotactic substances are
a.some of the bacterial or viral toxins .
b.degenerative products of the inflamed tissues.
c.several reaction products of the complement complex.
d.reaction products caused by plasma clotting .
4. phagocytosis depends on three selective procedures:
A-rough surface B-dead tissues have no protective prot. coats,
C- The immune system produce antibodies+Ba+C3 which attached to the receptors on phagocyte membrane this selection and phagocytosis process called opsonization.

18. Specific Functions of Different types of Leukocytes
Neutrophils:
1. the neutrophils have been called the body’s first line of defense against bacterial infection. In patients with bacterial infection the neutrophil count is greatly increased (neutrophilia). Lack of neutrophils called neutropenia.
2. Release lysosomal enzymes that kill microorganisms.They produce superoxide,H2O2 Hydroxyl ions all are lethal to bacteria. Myeloperoxidase catalyzes the reaction between the H2O2 & chloride ions to form hypochlorite it is a powerful bactericidal.
3. phagocytize microorganism and phagocytize 3-20 bacteria before it dies.
(Macrophages: phagocytizing 100 bacteria & contain lipases that digest thick lipid membranes of some bacteria example: (tuberculosis bacillus). .

19. Monocytes: are the largest type of leukocytes. 1
Monocytes: are the largest type of leukocytes. 1. Leave the circulation, enter tissues, enlarge and transformed into macrophages which are important in late stages of infection. 2 Produce chemicals such as prostaglandins, interferons and complement that are important in immune system response. 3. Macrophages are given specific names such as dust cells in lungs and kupffer cells in the liver. Macrophages are present in the skin, lymph nodes , bone marrow and spleen.
Lymphocytes:. are the smallest leukocytes.
2. Types are: T-lymphocyte. 2. B-lymphocytes which differentiated into plasma cells that produce antibodies or immunoglobulins (Igs). These antibodies responsible for destroying foreign antigens. 3. Natural killer cells.

20. Basophils:
1. Release chemicals such as histamine, bradykinin,serotinin & lysosomal enzymes which promotes inflammation. Release heparin which prevents clot formation. In allergic reactions basophil count are elevated (basophilia) is found in basophilic myelocytic leukaemia.
Eosinophils
release enzyme that inhibit inflammation caused by chemicals such as histamine. 2. Release enzymes that kill some parasite so in patients with parasitic infection eosinophils number greatly increased.They release hydrolytic enzymes, reactive oxygen& larvacidal polypeptide.
Mast Cells:
1. are heavily granulated wandering cells located at points of entry of microorganism into the body such as skin, lungs, GIT and urogenital tract. 2. Contain histamine which promotes inflammation. 3. Contain heparin which prevent clot. 4. have antibody IgE on their cell membrane.

26. INFLAMMATION when tissue injury occure,by chemicals,Ba,trauma
other causes; many substances released by the injured tissues and cause secondary changes in the surrounding uninjured tissues this entire changes is called inflammation.It is characterized by: 1.Vasodilatation increase blood flow. 2. increase permeability of the capillaries & fluid leak into interstitial spaces. 3.clotting of fluid (presence of fibrinogen). 4.Migration of large number of granulocytes & monocytes into tissues 5. Swelling of the tissue cells due to secretion of :A-Histamine
B-bradykinin C- Serotonin D-prostaglandin
E- Reaction products of complements, lymphokines released by T cells. ALL strongly activate the macrophages.

27. Walling Off; Effect of Inflammation
Results of inflammation is to wall off area of injury from remaining tissue.the tissue space and the lymphatic are blocked by fibrinogen.
Ex:Staphylococcus release toxic fatal substance inflamation develop rapidly much more than their multiplication.Streptococci reproduce & migrate through tissue.They do not cause walling off rapidly,It is a slow process it may cause death.
Tissue Macrophages are the first line of defence against infection, macrophages,histiocytes in the subcutenous tissue,alveolar macrophages in the lungs, microglia in the brain all have phagocytic action .They are activated by products of inflammation ,they enlarge migrate to the site of infection.

28. NEUTROPHILS; are the 2nd line of defense:
Margination,diapedesis,ameboid movement,
Chemotaxis , opsonization & phagocytosis;N count become in case of infection& called neutrophilia.
Third line of defense is the invasion of second macrophages into the inflamed area
Along with Neutrophils,Monocytes,enter the tissues. M are low in blood & bone marrow compared with the number of neutrophils( N ).
When monocytes enter the tissue they need 8 hours to swell &( several days to weeks) to form lysosomes.

29. The fourth line of defense is the production of the granulocytes & monocytes by the bone marrow it takes 4-5 days their production is stimulated by the products of inflammation.
Feedback Control of the Macrophages and
Neutrophil Responses
Many factors affect the control of macrophage response to inflammation five of them play an important roles, they are:1. Tumor necrosis factor (TNF).2.Interleukin-1(IL-1) 3. Granulocyte monocyte colony-stimulating factor (GM-CSF).
4.Granulocyte colony-stimulating factor (G-CSF).
5.Monocyte colony-stimulating factor (M-CSF).
They stimulate the bone marrow to increase the production of granulocytes,monocytes/macrophages. The process begin with tissue inflamation & ended in the formation of large number of defensive WBCs that remove the cause of inflammation.

31. Formation of pus
Neutrophils & macrophages engulf bacteria & necrotic tissue ( all neutrophils & most M )die.
A cavity is formed after several days in the inflamed tissues contain ( necrotic tissues, dead neutrophils , dead macrophages and tissue fluid) this mixture called pus.
After the infection is suppressed the dead cells and necrotic tissue after days autolyze,
The end product absorbed in to the surrounding tissues and lymph.

32. Leukopenia: occurs when the bone marrow produces very low WBCs leaving the body unprotected against many bacteria & other agents that might invade the tissues.Causes are irradiation x-ray,gamma rays,exposure to drugs or chemicals containing benzene or common antibiotics ex. Chloramphenicol ,thiouracil and others
Leukocytosis: is an abnormally high WBC count. Bacterial infection causes leukocytosis.
Leukemia: a tumor of the red marrow. Leukemia is characterized by greatly increased numbers of abnormal WBC's in the circulating blood.