quiz #2 - infections & disease Flashcards
ENDOGENOUS
within body, normally existing microbe (already existing yeast)
EXOGENOUS
outside of body, pathogen from environment (flu from influenza virus)
FIRST line of defense
mechanical barriers like epithelial surfaces:
-Intact skin & mucous membranes
-Oil & perspiration on skin
-Gag & cough reflex
-Peristalsis of GI tract
-Flushing action of tears, saliva, mucous
-Normal flora in gut
SECOND line of defense
inflammation, non-specific reaction
THIRD line of defense
acquired immune response (adaptive), leukocytes, antibodies, phagocytes
SOURCES of infection
Virus
Bacteria
Protozoa
Fungi
Helminths (worms)
Mycobacteria
Prions
SPREAD of infection within HOST (3 periods)
Incubation period: infected, no symptoms yet
Prodromal period: generalized symptoms like fatigue, loss of appetite, headache
Acute period: typical infection symptoms caused by damaged tissues
VIRULENCE
number of organisms & amount of time to start infectious process – measures strength of disease
TRANSMISSION
ingestion, inhalation, bites, contact with mucosa, transplacentally, injections, skin to skin contact, contact with blood/ bodily fluids, other contaminated items
PORTALS OF EXIT
feces, urine, vomit, tears, semen, open lesions, blood, saliva
POSSIBLE ROUTES (transmission)
-Contact: direct / indirect (through a fomite)
-Airborne: smaller particles float on air for hours
-Droplet: larger particles float on air for hours
-Vehicle: common sources → food & water
-Vector: carried by something else like mosquito / tick
RESERVOIR
person who is carrying contagious disease
CARRIER
person who has contagious disease, but does not develop symptoms
FOMITE
inanimate object that transmits infection disease (keyboard, doorknob, phone)
RISK FACTORS
lack of sleep, age, nutrition, hygiene, concurrent disease, hormonal imbalances, drug use
PATTERNS of infection - may produce:
-local damage (warts, welts)
-toxin that is poisonous (botulism)
-widespread systemic effects (HIV)
SPREAD of infection
Directly: produce enzymes that damage cell membranes
Via natural channels: move through membranes like meninges, pleura, peritoneum
Via nerves/ phagocytes: like herpes virus
MODE of ACTION
Virus: invade cells, invade DNA - change & interfere with normal cell processes → metabolism, growth, replication
-other organisms: cause cell to die in some way
NOSOCOMIAL infection
acquired in healthcare setting – hospital/ homecare
OPPORTUNISTIC infection
from impaired immune system – common in AIDS, HIV, transplant patients, older age, newborns, burn victims, chronically diseased
Clinical SIGNS & SYMPTOMS of infection
Systemic
Skin
Cardiovascular
Respiratory system
CNS
GI
Urinary system
