KIN 272 Chapter Notes - Chapter 21: Natural Killer Cell, Respiratory Burst, Adaptive Immune System
Document Summary
Chapter 21 the immune system: innate and adaptive body defenses. 21. 1 surface barriers act as the first line of defense to keep invaders out of the. Skin and mucous membranes constitute the first line of defense. Protective membranes line all body cavities and organs exposed to the exterior. Surface membranes provide mechanical barriers to pathogens. Some have structural modifications and produce secretions that enhance their defensive effects: The skin"s acidity, lysozyme, mucus, keratin, and ciliated cells are examples. 21. 2 innate internal defenses are cells and chemicals that act as the second line of defense. Phagocytes (macrophages and neutrophils) engulf and destroy pathogens that breach epithelial barriers. This process is facilitated when opsonins (antibodies or complement to which the phagocyte"s receptors can bind) attach to the pathogen"s surface. Natural killer (nk) cells are large granular lymphocytes that act nonspecifically to kill virus-infected and cancerous cells.
