1. BLOOD PHYSIOLOGY Lecture 4 White Blood Cells

2. Monocytes • Blood macrophage • Stem cell  monoblast  promonocyte  mature monocyte  blood  tissues  transfer into large tissue macrophyage (histocyte) • Functions: anti-inflamatory

3. Macrophage Function • Directly: phygocytosis of bacteria, dead cells • Indirectly cooperating with lymphocytes • Recognizing foreign body  take in foreign body process it and present it to lymphocytes

5. Lymphocytes • Heterogenous group of cells differ in • origin • migration pattern • Size • staining characters, • ultra structure • life span & function

6. LYMPHOCYTES • Morphological classification • small and large • Functional classifications • Thymus dependent (T lymphocytes) • Thymus independent (B lymphocytes)

7. Lymphopoiesis • Stem cell (thymus, lymphoid tissue & bone marrow)  lymphoblast  intermediate pyronophilic blast cell  lymphocytes (small, large) • Lymphocyte  lymphoblast (stimulated in culture by PHA, tuberculin).

8. Lymphocytes cont. • Lymphocytes enter blood stream: • Directly Through the vessel wall from lymphatic tissue; • Through Lymph in thoracic duct • Majority of lymphocytes in the circulation are small • Function: Immunity

9. T-Lymphocytes • Thymus-dependent: migrate from origin to thymus • Life spans 100-130 days. • Circulate between blood, tissues, lymph. • Types of T-lymphocytes • T-helper • T-cytotoxic • Natural killer • Functions • Cellular immunity (graft rejection, delayed hypersensitivity). • Role in antibody secretion.

10. B-Lymphocytes • Thymus-independent • Bird Bursa • Formed in bone marrow, germinal layer of lymph node, red pulp of spleen • Life span 2-7 days • Stimulated by antigen  large plasma cell ( produce antibody) • Function: Humoral immunity.

11. Leucocytosis • Increased WBC • Physiological • Diurnal morning  evening • After protein meal • After physical exercise • Stress or Adrenaline injection • Disease • Bacterial infection (tonsillitis, appendicitis • Worm infection

12. Leucopenia •  WBC • Malnutrition • Typhoid fever • Depressed bone marrow • Deficient Vit B12 or folic acid

13. Leukaemia • Cancer of white cells: chromosomal abnormality ccaused by chemical, radiation, and viruses • WBC > 50x103 • Types of leukaemia • Myeloblast leukaemia  myeloid cells • Lymphoblast leukaemia  lymphocytic cells • Acute or chronic • Accompanied by anaemia & bleeding

14. Platelets (karyocytes) • Formed in bone marrow • Stem cells  Promegakaryocyte  megakaryocyte  breaking pieces of cytoplasm (platelets) • Platelet count = 250000/ml • Functions • Adhere to injured site of blood vessel to prevent bleeding • Important for clot formation, retraction

17. Reticulo-endothelial/ macrophage system RES • Are groups of Cells: • Blood macrophages (Monocytes) • Tissue macrophages (Histocytes) • Macrophages lining lymph sinuses in lymph nodes & Blood sinuses in liver, spleen.

18. Reticuloendothelial system • Functions of the RES: • Phagocytosis: Bacterial, dead cells, foreign particles • Breakdown of Hb • Immune function: processing antigen and antibodies production • Storage of iron