Intro to rad exam 2

what are microorganisms

living organisms too small to be seen w naked eye

what do microorganisms include

bacteria

viruses

protozoa

prions

fungi

whats normal flora

microorgs that live on or inside the body w/o causing infection or disease

what do normal flora aid in

skin preservation

digestion

protect us from harmful orgs that can cause infection

what kind of organisms cause infection

pathogenic

what are the 3 factors for pathogens

• multiply in large numbers and cause obstruction

• cause tissue damage

• secret exotoxins

what side affects do exotoxins cause

• elevated body temp

• nausea/vomitting

• sock

what are the types of pathogens

bacteria

fungi

viruses

prions

protozoa

what is the smallest known disease causing organisms? what is their size?

viruses, 20-300nm

which is bigger viruses or prions

viruses

what is a virion

fully developed viral particle made of genetic material - DNA or RNA protected by capsid

what is a capsid

protective outer protein coating on virions

why are viruses considered parasites?

they cant survive without a host

how do virions help produce new viruses

attach to host cell, inserts own genetic info, then redirects host cell to produce new viruses

true or false: viruses are affected by antibiotics

false

true or false: viruses may lie dormant for extended period of time then manifest in illness

true

diseases cause by viruses

• epstein - barr (mono)

• varicella (chicken pox)

• herpes zoster (shingles)

what do bacteria have

cell wall and atypical nucleus that lack nucleus

what is essential to the survual of bacteria and a target of destruction by antibodies

cell wall

3 classes of bacteria

• cocci (spherical)

• bacilli (rod shaped)

• spirals

what are the o2 classifications for bacteria

• obligate aerobes

• anaerobes

what do some bacteria produce

endospores

endospores

resitant form of bacterium produced when conditions aren’t optimal

where do most endospores live

in the soil mainly and germinate in favorable coniditons and revitalize

diseases caused by bacteria

• streptococcal group A:streptococcalpharyngitis (strep throat) necrotizing fascitis

• E coli: infectious diarrhea; hemolytic uremic syndrome

• m tuberculosis: tuberculosis

whats the smallest and least understood pathogen

prion

how big are prions

2-5 nm

what are prions thought to be

infectious proteins

method of transportation for prions

unknown

what are prions capable of

transforming healthy protein in nerve cells into more prions

what pathogen is resistant to the bodys natural defenses

prions, they continue to multipy and cause irreversible nerve damage

what pathogen causes scrapie in sheep

prions

what pathogen cuases Creutzfeldt disease in humans

prions

classic form of Creutzfeldt disease

rare, occurs for no reason or from inheriting prion

variant form

infectious - caused by contaminated products like infected corneal transplants or infected meat

what is caused by both forms of Creutzfeldt disease

sponge like changes in the brain that lead to dementia

what are the forms of fungi

• single celled yeast

• molds - long branched filament structures

which is bigger fungi or bacteria

fungi

what skin infection are from fungi

athloetes foot and ringworm

what are some respiratory infections from fungi

• histoplasmosis- caused by breathing in spores from soil w bird or bat droppings

what are some opportunistic infections from fungi

pneumocystis carinii pneumonia - lung infection affecting immunocompromised people

what are protozoa

cpm[lex single celled animals - exist as free living organisms

how how protozoa classified

by motility

what forms can protozoa produce

cystic forms to survive outside of host

what are some diseases with protozoa

• amebiasis + giardiasis: affect gastro tract and cause disease

• trichomoniasis: STD - causes greenish yellow discharge

• toxoplasmosis: contact w cat feces or eating undercooked meat, affects blood and lymphatic vessels causing congenitalinfection in fetus or neuro impairment in immunocompromised

opportunistic infection

normal flora can cause infections when located outside usual environment or when host immune system is compromised

example of opportunisstic infection

e coli is normal in gastro tract, becomes pathogenic if it enters bladder

what is the cycle of infection IN ORDER

• infectious organisms

• reservoir of infection

• portal of exit

• susceptible host

• portal of entry

• transmission of diease

what are infectious organisms in the cycle of infection

microorgs capable of causing disease, virulence factors distinguish pathogens from nonpathogenic and normal flora

what is a reservoir of infection in the cycle of infection

place where pathogens can thrive in sufficient #’s to pose a threat

what must a reservoir of infection have

• moisture

• nutrients

• suitable temperature

what is a portal of exit in the cycle of infection

any route through which blood, body fluids, excretions, secretions leave the body

what is a susceptible host in the cycle of infection

humans are favorable host environment b/c of our abundance of organic nutrients

nosocomial infection

hospital- acquired infection (HAI)

what is a portal of entry in the cycle of infection

route by which microorgs gain access into the susceptible

what is transmission pf disease in the cycle of infection

direct contact, fomites, vectors, droplet contamination, vehicles, airborne transmission

what is direct contact

pathogens spread direct contact w another person or a contaminated object

what infections are spread through direct contact

syphilis, HIV infections, staph

what is a fomite

inanimate object that has been in contact w an infectious microorganisms

what are examples of fomites

food, water, rad equipment

what is a vector

usually an arthropod (fly or mosquito) that can transmit disease from host to host

what is a vehicle

any medium that transports microorganisms

examples of vehicles

contaminated food, water, drugs, blood

what is droplet transmission

pathogens disseminate through large particulate droplets expelled from the patient during coughing, sneezing, or even talking

what infections are transmitted through droplet

rubella, mumps, influenze, and adenovirus

what is airborne transmission

pathogenic organisms remain suspended in air for long periods on aerosol droplets or dust

how does airborne transmission measure

5 microns or smaller

what diseases are transmited through airborne

tuberculosis, varicella, rubella

what are the 3 different defenses the body has against infection

• natural resistance

• acquired immunity (long term)

• passive immunity (short term)

what is natural resistance

provided by mechanical barriers of intact skin and mucus membranes

what is acquired immunity

long term - occurs when an individual develops antibodies to a particular organism as a resilts of either infection or immunization

what is passive immunity

short term - individuals receive antibodies produced outside their body. mother passes to newborn in utero/breast milk. also lab developed emergency immunization