Terminology.docx

Pathology - the study of disease Etiology - the study of the cause of a disease Pathogenesis - the development of disease Infection - invasion or colonization of the body by pathogens Disease - an abnormal state in which body is not performing Symptoms - Changes in body function that are felt by a p...

Pathology - the study of disease Etiology - the study of the cause of a disease Pathogenesis - the development of disease Infection - invasion or colonization of the body by pathogens Disease - an abnormal state in which body is not performing Symptoms - Changes in body function that are felt by a patient Signs - Changes in a body that can be measured or observed Syndrome - A specific group of signs & symptoms that accompany a disease Communicable disease - A disease that is spread from one host to another Contagious disease - disease that is easily & rapidly spread Noncommunicable disease - A disease that is not spread from one host to another Local infection - Pathogens are limited to a small area of the body Systemic (generalized) infection - An infection throughout the body Primary infection - Acute infection that causes the initial illness Secondary infection - Caused by opportunistic pathogens after a primary infection Reservoir - continual sources of infection Human reservoirs - Sick people or “carriers” with no signs & symptoms Non-living reservoirs - Contaminated inanimate objects Direct contact transmission - requires close association (touching) between infected person and susceptible host Indirect contact transmission - spreads to host by a contaminated non-living object called a fomite Droplet transmission - transmission via airborne droplets less than 1 meter Airborne - transmission via airborne droplets more than 1 meter Mechanical vector transmission - Arthropod vector carries pathogen outside its body called “passive transport” of pathogen Biological vector transmission - Arthropod vector supports life cycle of pathogen in its body Pathogen transmitted via bites called “active transport” of pathogen Pathogenicity - Ability of microbe/pathogen to cause disease in a host Virulence - The enhanced ability of a pathogen to cause infection Virulence factor - Characteristic or trait of the pathogen that makes it harmful Mechanisms of Pathogenicity - The different ways by which a microbe can cause an infectious disease Parenteral route- Non-oral entry, pathogens directly deposited into tissue or bloodstream Adherence (adhesion) - Ability of pathogens to attach to host tissues/cells Coagulase - helps form blood clot stops blood flow host defenses cannot reach bacterium; bacteria can also surround themselves inside a clot Kinase - Breaks down blood clot surrounding the bacterium bacterium free to spread throughout body Hyaluronidase - Breaks down hyaluronic acid in connective tissue Collagenase - Breaks down collagen in connective tissue IgA protease - Destroys IgA antibodies Toxin - Poisonous substance (acting as Ag) produced by pathogens Toxigenicity - Ability of a pathogen to produce a toxin Toxemia - Presence of toxin in the bloodstream Toxoid - A chemically modified toxin which is no longer toxic Antitoxin - Antibody against a toxin Immunogen - act as an Antigen Immune system - protects the human host Immunity - ability to fight-off pathogens & prevent disease Host defenses - ability of host to remove pathogen(s) in order to prevent disease Commensal microbes - One organism benefits while other organism (host) is unaffected Beneficial microbes - Microbes provide something to the host Opportunistic microbes - Microbes that act as pathogens under certain circumstances Competitive Exclusion “microbial competition” - Normal microbiota compete with pathogens (invading microbes), leading to decreased populations of pathogenic bacteria Granulocytes - leukocytes with granules in their cytoplasm that are visible with a light microscope Basophils - release histamine; involved in allergic responses Eosinophils - toxic against parasites and worms Neutrophils - phagocytic; work in early stages of infection; First responders Monocytes -travel in blood & will mature into macrophages in tissues where they become phagocytic cells Phagocytosis - ingestion of microbes or other substance by a phagocyte Phagocyte - non-specific host cell capable of phagocytosis Chemotaxis - Release of chemical signals (cytokines) by pathogen attract phagocytes Adherence - Attachment of phagocyte to surface of the pathogen Ingestion - Endocytosis of pathogen form a phagosome merges with lysosome form a phagolysosome inside phagocyte Digestion - Pathogen is digested inside a phagolysosome Capsule - pathogen too big to be engulfed Capsule - pathogen too big to be engulfed Mycolic acid - a waxy lipid ; inhibits lysosome enzymes of phagocyte bacteria and multiply inside phagocyte & hide from immune system Opsonization - Complement proteins coat surface of pathogen; promotes attraction/attachment of phagocyte to pathogen Inflammation - Complement proteins bind mast cells; mast cells release histamine increase blood vessel permeability; chemotactic attraction of phagocytes Cytolysis - Complement proteins create a membrane attack complex (MAC); MAC creates a hole/channel in pathogen’s cell wall/cell membrane Immunology - Study of host defenses against foreign substances (antigens) Antigen (Ag) - Substance that stimulates a certain immune response in the form of antibody production Antibody (Ab) - Protective proteins made by the host in response to certain antigens Humoral Immunity - Fights invaders and threats outside of the cell (extracellular Ag’s) Cell-Mediated (Cellular) Immunity - Attacks antigens that have entered the cell (intracellular Ag’s) Helper T cells (TH cells) - Activate TC cells involved in cell-mediated immunity Activate certain B cells (memory B cell) to produce Ab’s (these are “T-dependent” B cells) Cytotoxic T cells (TC cells) - AKA “killer” T cells; destroy target cells on contact Regulatory T cells (TR cells) - Suppresses/turns-off immune response when it is not needed Delayed Hypersensitivity T cells (TD cells) - Produces a delayed and exaggerated immune response that can occur from days to years later Memory T cells - Promote a relatively “faster” & stronger immune response than the primary immune response as a result of 2nd encounter with the same Ag