Chapter 5 Pahtophysiology Terms Flashcards
Infection
a state of cellular, tissue, and sometimes even organ destruction resulting from invasion by microorganisms
Resident flora
microorganisms that live on or within the body in nonsterile areas, such as the skin, mucous membranes,bowel, rectum or vagina, without causing harm
Pathogen
disease producing microbe
pathogenicity
qualities that promote the production of disease- involves multiple factors including the pathogen’s potency, invasiveness, ability to evade the immune system, speed of replication, production of toxins, adherence of the human host cell, and degree of tissue damage that is elicited
virulence
potency of the pathogen indicated by the ratio of the number of cases of disease in a population compared wiht the number of people exposed to the micororganisms
Infectivity
proportion of exposures needed to cause infection in an individual based on the pathogen’s ability to enter, survive in, and multiply in the host
Toxigenicity
ability of the pathogen to produce harmful toxins that increase host cell and tissue damage
Antigenicity
level to which a pathogen is viewed by the host immune system as foreign. A more antigenic pathogen elicits a more prominent immune response
Antigenic variability
process of eluding the human host defenses and is often a result of altering teh antigens present within or on the surface of the microorganism. Many infectious microorganisms can escape human host defenses though slight genetic variations unrecognized by the host
Pathogenic defense mechanism
ways in which many pathogens have developed ways to avoid destruction by the host, such as through thick protective capsules, which prevent phagocytosis
coinfection
phenomena of hosting two or more pathogens simultaneously. certain pathogens are more likely to be transmitted and to coexist in the host. Coinfection presents a greater challenge to the immune system
Superinfection
when an infection arises in addition to teh one that is already present. Often results from a compromised host defenses and overproliferation of resident flora
Obligate parasites
require the host for metabolism and reproduction
Facultative parasite
may live on the host but can also survive independently
Bacteria
single-celled microorganisms- most can reproduce outside of host cells
Aerobic
require oxygen for growth
Anaerobic
do not require oxygen for growth
Endotoxin
complex of phospholipid- polysaccharaide molecules that form the structural component of the gram-negative cell wall. Causes inflammatory mediators to be released, leading to massive inflammatory response
Pyogenic Bacteria
endotoxin containing bacteria that can induce fever
exotoxins
potent substances, often bacterial-derived proteins, released into the surrounding tissues that case local or systemic injury in the host
Virus
considered obligate intracellular parasite
Virions
particles released by the virus outside of the cell, which can enter and infect nearby cells
Latency
dormancy
yeasts
unicellular form of fungi
mold
multicellular fungi
pseudohyphae
elongated chains formed by yeast through budding