Microbe Human interactions Flashcards
microbes that engage in mutual or commensal associations with humans belong to the?
normal resident microbiota
A condition in which pathogenic microbes penetrate hosts defenses, enter tissue, and multiply
infection
microbe acting as infection that causes damage or disruption to tissues and organs.
pathogen
an infection that causes damage or disruption to tissues and organs
infectious disease
colonization of the body involves a constant.
“give and take”
microbes that occupy the body for only short periods
transients
microbes that become established
residents
In many cases, microbiota benefits host by preventing overgrowth of harmful microbes.
microbial antagonism
what is the largest and most accessible organ?
skin
what cling to the surface but do not grow there; influenced by hygiene.
transients
stable, predictable, less influenced by hygiene, primarily bacteria and yeasts
residents
variations in flora distribution due to shifting conditions in
pH, oxygen tension, anatomy
what is the most diverse and unique flora of the body?
microbiota of the mouth
intestinal environment favors
anaerobic bacteria
what are the sites of the genitourinary tract?
females- vagina and outer opening of urethra
male- anterior urethra
major factors in development of infection finding a portal of entry.
skin
GI tract
respiratory tract
urogenital tract
endogenous biota
attaching firmly
fimbriae
capsules
surface proteins
viral spikes
hooks
existing hosts: portals of exit
respiratory tract, salivary glands
skin cells
fecal matter
urogenital tract
blood
introducing known microbes back into the body
probiotics
what are factors that weaken hosts defenses and increase susceptibility to infection?
old age, extreme youth
genetic defects
surgery organ transplants
capable of causing disease in healthy persons with normal immune defenses
true pathogens
cause disease when the hosts defenses are compromised or when they grow in part of the body that is not natural to them.
opportunistic pathogens
characteristic route a microbe follows to enter the tissues of the body.
portals of entry
originate from source outside the body ex. Flu
exogenous
already exist on or in the body (normal flora)
endogenous
characteristic or structure that contributes to the ability of a microbe to cause disease
virulence factor
portals of skin
skin
gastrointestinal tract
respiratory tract
urogenital tract
transplacental
pathogens that infect during pregnancy STORCH
syphilis
toxoplasmosis
other diseases
rubella
cytomegalovirus
herpes simplex virus
minimum number of microbes require for infection to proceed
infectious dose (ID)
microbes with a small IDs have a
greater virulence ex. measles
what are the 3 phases of an infection
phase 1 becoming established
phase 2 attaching to the host
phase 3 invading and becoming established
microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on hosts and pathogens.
adhesion
how are microbes attach to the host
fimbrae
flagella
glycocalyx
cilia
suckers
hooks
barbs
bacteria produced extracellular enzymes that dissolve barriers and penetrate through or between cells to invade underlining tissues
exoenzymes
toxins secreted by bacteria damage target cells which die and begin to slough off
toxins
specific chemical product of microbes plants and some animals that has poisonous effects on other organ
toxinoses
not secreted but released after the host cell is damaged
endotoxin
secreted by a living bacterial cell into the infected tissue
exotoxin
four distinct stages of clinical infections
incubation period
prodromal stage
period of invasion
convalescent period