MICR 270 Lecture Notes - Lecture 2: Natural Killer Cell, Innate Immune System, Complement System
7 Mar 2017
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Document Summary
Immune system functions as a singular unit despite its functional separations. Innate immune system: present in all multicellular organisms, oldest host defense system, operate non-specifically, external - unbroken skin, mucous membranes of respiratory/alimentary. Internal - phagocytic cells, complement system and cytokines: barrier types, physical. Lungs - cilia of respiratory tract prevent trapped particles form reaching your lungs: tears - contains lysozyme, attacks bacteria and prevents infection, mucus - microorganisms get caught, kept out of body. Skin - protects against bacterial invasion unless broken: cilia - sweep foreign particles up to throat so they can be coughed/sneezed out. Search for pathogens to engulf: phagocytic, most common leukocyte (70% of all leukocytes, 12 hours in blood, enter tissue for 1-3 days. Short-lived: macrophages, phagocytic, travel across circulatory system by moving across cell membrane of vessels, called monocytes in circulation, can present antigens to adaptive system, dendritic cells, phagocytic, present in context of mhc.
