Leukocytes

1. General Structure and Function
   

1. protection from microbes, parasites, toxins, cancer
2. 1% of blood volume; 4-11,000 per cubic mm blood
3. diapedesis - can "slip between" capillary wall
4. amoeboid motion - movement through the body
5. chemotaxis - moving in direction of a chemical
6. leukocytosis - increased "white blood cell count" in response to bacterial/viral infection
   
7. granulocytes - contain membrane-bound granules (neutrophils, eosinophils, basophils)
   
8. agranulocytes - NO membrane-bound granules (lymphocytes, monocytes)
   

2. Granulocytes - granules in cytoplasm can be stained with Wright's Stain; bilobar nuclei; 10-14 micron diameter; all are phagocytic cells (engulf material)
   

1. Neutrophils - destroy and ingest bacteria & fungi (polymorphonuclear leuks.; "polys")
   

1. most numerous WBC (Never Let Monkeys Eat Bananas)
2. basophilic (blue) & acidophilic (red) - LILAC
3. defensins - antibiotic-like proteins (granules)
4. polymorphonuclear - many-lobed nuclei
5. causes lysis of infecting bacteria/fungi
   
6. HIGH poly count --> likely infection
   

2. Eosinophils - lead attack against parasitic worms
   

1. only 1-4% of all leukocytes
2. two-lobed, purplish nucleus
3. acidophilic (red) granules with digest enzymes
4. phagocytose antigens & antigen/antibody complex
5. inactivate chemicals released during allergies
   

3. Basophils - releases Histamine which causes inflammation, vasodilation, attraction of WBCs
   

1. RAREST of all leukocytes (0.5%)
2. deep purple U or S shaped nucleus
3. basophilic (blue) granules with HISTAMINE
4. related to "mast cells" of connective tissue
5. BOTH release Histamine with "IgE" signal
   
6. antihistamine - blocks the action of Histamine in response to infection or allergic antigen

3. Agranulocytes - WBCs without granules in cytoplasm

1. Lymphocytes - two types of lymphocytes

1. T lymphocytes - (thymus) respond against virus infected cells and tumor cells
2. B lymphocytes - (bone) differentiate into different "plasma cells" which each produce antibodies against different antigens
3. lymphocytes primarily in lymphoid tissues
4. very large basophilic (purple) nucleus
5. small lymphocytes in blood (5-8 microns)
6. larger lymphocytes in lymph organs (10-17 mic)
   

2. Monocytes - differentiate to become macrophages; serious appetites for infectious microbes
   

1. largest of all lymphocytes (18 microns)
2. dark purple, kidney shaped nucleus

Category: Pathology Notes