BIOL 1082 Lecture Notes - Lecture 20: Microorganism, Histocompatibility, Critical Role
Document Summary
Defenses against pathogens i (reading: concepts: 43. 1-43. 2 in textbook, skip section. Generation of b and t cell diversity on pgs. 955-956: describe the barrier and internal defenses that function as the innate immune system of vertebrates. Barrier defenses: skin, mucus membranes lining the digestive, respiratory, urinary, and reproductive tracts. Some migrate throughout the body, whereas others reside permanently in organs and tissues where they are likely to encounter pathogens: dendritic cells (phagocytic cell) mainly populate tissues, such as skin, that contact the environment. They stimulate against pathogens they encounter and engulf: eosinophils (phagocytic cell), often fount beneath mucosal surfaces, are important in defending against multicellular invaders, such as parasitic worms. Upon encountering such parasites, eosinophils discharge destructive enzymes: natural killer cells circulate through the body and detect the abnormal array of surface proteins characteristic of some virus-infected and cancerous cells. Natural killer cells do not engulf stricken cells.
