20 terms

Spring Anatomy CH 21 Immune System

immune system
consists of diverse molecules and immune cells that make up lymphoid tissue
non-specific defense
responds quickly and consists of:
i. first line of defense- skin and mucosa prevent entry of microorganisms, external barrier
ii. second line of defense- antimicrobial proteins, phagocytes, and other cells
specific defense
iii. third line of defense- mounts attack against particular foreign substances
surface barrier
skin, mucous membranes, and their secretions make up the first line of defense; keratin and mucosa
presents a physical barrier to most microorganisms, resistant to weak acids and bases, bacterial enzymes, and toxins
epithelial chemical barriers
epithelial membranes produce protective chemicals that destroy microoganisms; skin acidity 3 to 5 pH which inhibits bacterial growth
respiratory tract mucosa
mucous-coated hairs in the nose trap inhaled particles, ciliated- cilia sweep dust and bacteria away from lower respiratory passages swallowed and enters stomach
WBC, phagocytic, wanders through loose connective tissue, absorb oxygen to form Hydrogen Peroxide and hyperchlorite which are both highly toxic
WBC, attacks worms such as tapeworms, produces hydrogen peroxide and toxic proteins that act as neurotoxins
WBC, secrete chemicals that activate neutrophils and eosinophils, release histamine that increases blood flow by vasodilation, secretes heparin that inhibits formation of blood clots that would impede leukocyte mobility
WBC, T-cells 80%, B-cells 15%, NK cells 5%
WBC, transform to macrophages, microglial cells in nervous tissue, kupffer cells in the liver, alveolar cells in the lung
antimicrobial proteins
enhance the innate defenses by attacking microorganisms directly and hindering microorganisms' ability to oreproduce
EX. interferon, complement proteins
genes that synthesize IFN are activated when a host cell is invaded by a virus, leave the infected cell and enter neighboring cells
IFN alpha
1st drug to have some success treating hepatitis C genital warts
IFN beta
treat patients with multiple sclerosis
30 or so proteins that circulate in the blood in an inactive form. major mechanism for destroying foreign substances in the body, synthesized in the liver
classical pathway
linked to the immune system, depends on the binding of antibodies to invade organisms
alternative and lectin pathway
require no antibodies and belong to non-specific defenses