MCB 100 exam 3 UPDATED ACTUAL Questions and CORRECT
Answers
infection when another organism evades external and some internal defenses, multiplies
and becomes established
epidemiology the study of the transmission of diseases within populations. The application of
these studies to control public health problems
where do pathogens come from? reservoirs
-most cannot survive for long outside host
types of reservoirs -animal
-human
-nonliving
zoonoses -diseases that spread from animal to humans
-direct contact with animals, eating them, bloodsucking
-difficult to eradicate, $
human reservoirs -infected individuals spread through close contact
-asymptomatic-can infect others
-some get sick, while others don't
-healthy carrier may have defense system that protects them
nonliving reservoirs -soil,water,food
-contamination by feces or urine
portals of entry skin, mucous membranes, placenta
-entry via parenteral route circumvents the usual portals
mucous membrane -respiratory (most common) and intestinal (needs to survive acid pH) tracts where
body interacts with outside
-line body cavities
-provide moist, warm environment
-entry nose, mouth eyes
Pathogenicity ability of microorganism to cause disease
virulence -degree of pathogenicity
-virulence factors contribute to virulence; adhesion, biofilms,extracellular
enzymes, toxins,antiphagocytic factors
adhesion -attachment first step of colonization
-if microbe doesn't attach, body flushes invaders out
, extracellular enzymes -proteins secreted by pathogen
-many dissolve structural chemicals in body
-help pathogen maintain infection, invade host cells and tissues, and avoid bodys
immune defenses
-have important roles in the virulence pathogens (mutant strains of pathogen that
do mot secrete these enzymes are often virulent)
toxins -chemicals that harm tissues or trigger host immune responses that cause damage
-toxemia refers to the presence of toxins in the bloodstream
-exo(larger peptides and proteins) and endo(membrane components)
Antiphagocytic factors -factors prevent phagocytosis by hosts phagocytic cells
-allow pathogens to remain in a host for a longer time
bacterial capsule
-composed of chemicals not recognized as foreign
-slippery and difficult for phagocytes to engulf
antiphagocytic factors
-prevent fusion of lysosome and phagocytic vesicles
-leulocidins directly destroy phagocytic white blood cells
clearance of pathogens -leave host through portals of exit
-many portals of exit are the same as portals of entry
-pathogens leave hosts in materials the body secretes or excretes
-immune system eliminates them
portals of exit -skin-erupting or oozing from wounds
-mucous fluids
-elimination by immune system
transmission -how a pathogen gets from a reservoir or portal of exit to another hosts portal of
entry
-contact
-vehicle borne
-vector borne
contact transmission direct contact
-body contact between hosts
-within single individual
indirect contact
-are spread from host to host by fomites (inanimate objects)
droplet
-mucus, exhaling, coughing and sneezing
Answers
infection when another organism evades external and some internal defenses, multiplies
and becomes established
epidemiology the study of the transmission of diseases within populations. The application of
these studies to control public health problems
where do pathogens come from? reservoirs
-most cannot survive for long outside host
types of reservoirs -animal
-human
-nonliving
zoonoses -diseases that spread from animal to humans
-direct contact with animals, eating them, bloodsucking
-difficult to eradicate, $
human reservoirs -infected individuals spread through close contact
-asymptomatic-can infect others
-some get sick, while others don't
-healthy carrier may have defense system that protects them
nonliving reservoirs -soil,water,food
-contamination by feces or urine
portals of entry skin, mucous membranes, placenta
-entry via parenteral route circumvents the usual portals
mucous membrane -respiratory (most common) and intestinal (needs to survive acid pH) tracts where
body interacts with outside
-line body cavities
-provide moist, warm environment
-entry nose, mouth eyes
Pathogenicity ability of microorganism to cause disease
virulence -degree of pathogenicity
-virulence factors contribute to virulence; adhesion, biofilms,extracellular
enzymes, toxins,antiphagocytic factors
adhesion -attachment first step of colonization
-if microbe doesn't attach, body flushes invaders out
, extracellular enzymes -proteins secreted by pathogen
-many dissolve structural chemicals in body
-help pathogen maintain infection, invade host cells and tissues, and avoid bodys
immune defenses
-have important roles in the virulence pathogens (mutant strains of pathogen that
do mot secrete these enzymes are often virulent)
toxins -chemicals that harm tissues or trigger host immune responses that cause damage
-toxemia refers to the presence of toxins in the bloodstream
-exo(larger peptides and proteins) and endo(membrane components)
Antiphagocytic factors -factors prevent phagocytosis by hosts phagocytic cells
-allow pathogens to remain in a host for a longer time
bacterial capsule
-composed of chemicals not recognized as foreign
-slippery and difficult for phagocytes to engulf
antiphagocytic factors
-prevent fusion of lysosome and phagocytic vesicles
-leulocidins directly destroy phagocytic white blood cells
clearance of pathogens -leave host through portals of exit
-many portals of exit are the same as portals of entry
-pathogens leave hosts in materials the body secretes or excretes
-immune system eliminates them
portals of exit -skin-erupting or oozing from wounds
-mucous fluids
-elimination by immune system
transmission -how a pathogen gets from a reservoir or portal of exit to another hosts portal of
entry
-contact
-vehicle borne
-vector borne
contact transmission direct contact
-body contact between hosts
-within single individual
indirect contact
-are spread from host to host by fomites (inanimate objects)
droplet
-mucus, exhaling, coughing and sneezing
