Cells and Tissues of The Immune System PDF

CELLS AND TISSUES OF THE IMMUNE SYSTEM Dr. HÜSNİYE IŞIN Components Of Blood Cells of the immune system Leukocytes: LYMPHOID - lymphocytes of different types MYELOID - dendritic cells, monocytes/macrophages and granulocytes; Other cells also involved in imm...

CELLS AND TISSUES OF THE IMMUNE SYSTEM Dr. HÜSNİYE IŞIN Components Of Blood Cells of the immune system Leukocytes: LYMPHOID - lymphocytes of different types MYELOID - dendritic cells, monocytes/macrophages and granulocytes; Other cells also involved in immunity: endothelial cells; epithelial cells e.g. keratinocytes; stromal cells of bone marrow etc Cells of the immune system All leukocytes are generated in primary lymphoid tissue by the process of haematopoiesis. The lymphoid and myeloid cells follow different differentiation pathways but both are derived from the haematopoietic stem cell, HSC Granulocytes Front line of attack during immune response~ part of innate immune response Identified by characteristic staining patterns of “granules” Released in contact with pathogens Proteins with distinct functions: killing, regulation of other cells, tissue remodeling All have multilobed nuclei Neutrophils One of the main effector cells in the innate immune system 50-70% of white blood cells Released from bone marrow, circulate 7-10 hrs, enter tissues, live only a few days Numbers & recruitment increase during infections~ “leukocytosis” diagnostic shown to kill microorganisms by phagocytosis 100 years ago Main cellular component of pus Neutrophils Named based on staining qualities of granules Multilobed nucleus= polymorphonuclear leukocyte= PMN Neutrophilic granules stain lightly blue to pink 7-10 hrs in blood, then migrates into tissues First responders- Motile & phagocytic “Leukocytosis” indicates infection Extracellular “traps” Basophils