nonspecific barriers, nonspecific denfenses and the immune system
what is the nonspecific barrier?
a rapid response to a wide range of pathogens (germs).
mucus and skin.
what mechanism does the skin provide?
it's a physical hotile barrier covered with oily and acidic secretions from sebaceous (fat) and sweat glands.
what are examples of antimicrobial proteins?
where are they contained in?
Lysozymes: breaks down the cell walls of bacterias.
salaiva, tears and other secretions found on mucus membranes.
what are cilias?
a line the lungs serve to sweep invaders out of the lungs.
what is the gastric juices of the stomach used for? what's it made up of?
hydrochloric acid or enzymes and it kills most microbes.
what is the nonspecific defense?
consists of mechanisms that indiscriminately challenge foreign invaders.
what are phagocytes?
white blood cells that engulf pathogens.
what are NK cells?
Natural killer cells a.k.a lymphocytes and it kills pathogen infected body cells.
what are complements?
a group of about 20 proteins that "complement" defense reactions. They help attract phagocytes to foerign cells and help destroy foreign cells by cell lysis (breaking open the cell)
what are Interferons? (IFN)
substances secreted by cells invaded by viruses and stimulate neighboring cells to produce proteins that help them fight agains viruses.
What is the inflammatory response? (relate to police defense system)
a chemical area is sounded and injured cells nearby release chemicals that initiate defensive actions (calling 911)
Vasodilation then occurs (dilation of blood vessels) and increases blood supply to the damaged areas. This causes a redness and increases temperature so that white blood cells are stimulated and pathogens are inhospitable. (Sudden flood of police cars, "traffic occurs")
phagocytes arrive at the site and engulf pathogens and damaged cells. They find this place by chemotaxis which is the movement of cells in responce to chemical gradients provided by the alarm chemicals. Complement helps pagocytes engulf foreign cells.
What is the immune system?
the third line of defense. It consists of mechaisms that target specific antigens
what are antigens?
any molecule that can be identified as foreign or nonself. Once an antigen is recognized, an agent is released that targets the specific antigen.
what are the five tasks that the immune system accomplishes?
recognition, lymphocyte selection, lymphocyte activation, destruction of the foreign substance and memorization
what is recognition?
the antigen is recognized as nonself. MHC (major histocompability complex) is used for identification.