Chp 14 Flashcards
cram this in your BRAIN (36 cards)
How do pathogens differ from normal flora?
Pathogens are harmful microorganisms which can cause disease, while normal flora are microbes that engage in mutual or commensal associations
Where are most of the normal flora in the human body found?
In areas that have contact with the outside environment (none in internal organs, tissues and fluids)
How do transient flora differ from resident flora?
Transient flora occupy the body for only a short amount of time and is influenced by hygiene
Resident flora are microbes that becomes established in our body (stable, predictable and less influenced by hygiene)
How do normal flora protect humans against infections?
- Prevent overgrowth of other harmful microbes (microbial antagonism)
^^ works by competing for nutrients, providing harmful substances to invading microbes, and affects pH and available oxygen
An infection that occurs when normal flora is introduced to a site that was previously sterile is known as ____________
Endogenous infection
Which group of people are at risk for endogenous infections?
Newborns
How do true pathogens differ from opportunistic pathogens?
True pathogens infect anyone, including healthy individuals whereas opportunistic pathogens only infect those with already compromised immune systems
List different portals of entry.
- Skin: nicks, abrasions, punctures, incisions
- GI tract: food, drink, and other ingested materials
- Respiratory tract: oral and nasal cavities (MOST COMMON)
- Urogenital tract: sexual displaced organisms
- Endogenous biota
- Transplacental
Describe three different adhesion methods used by pathogens.
- Fimbriae
- capsules/slime
- Viral spikes (like influenza and HIV)
- Hooks
Enzymes releasing outside of the cell are known as __________
Exoenzymes
Differentiate between endotoxins and exotoxins
Endotoxins are toxins not secreted but released after the cell is damaged
- Composed of lipopolysaccharide (part of outer membrane of gram negative cell walls
Exotoxins are released outside of the cell and is secreted by a living bacterial cell into the infected tissue
- Strongly specific for a target cell
- Hemolysins
- Active and Binding toxins
- only released when bacteria is damaged
Differentiate between localized, focal, and systemic infections
Localized: microbes enter body and remains confined to specific tissue
Focal: infectious agent breaks loose from local infection and is carried to other places
Systemic: infection spreads to several sites and tissue fluids usually in the blood stream
Differentiate between primary and secondary infections.
Primary infection: initial infection
Secondary infection: another infection by a different microbe
What are acute and chronic diseases?
Are the common cold and AIDS acute or chronic diseases?
Acute: comes on rapidly, with severe but short-lived effects
Chronic: progress and persist over a long period of time
Cold: acute
AIDS: chronic
Differentiate between signs and symptoms of an illness.
Signs are noticeable and observable on the outside whereas symptoms are subjective experiences reported by the patient
Describe ports of exit.
Any pathway a pathogen can use to exit its host or reservoir
- Respiratory tract
- Salivary glands
- Skin cells
- Fecal matter
- Urogenital tract
- Blood
What are latent infections?
An infection that remains dormant and undetectable until it gets reactivated
Differentiate between a reservoir and a source of infection.
Reservoir: primary habitat of pathogen in the natural world (human or animal carrier, water, soil, plants)
Source: individual or object from which an infection is actually acquired
What is the difference between asymptomatic carriers and passive carriers?
Asymptomatic carriers show no symptoms now but later on begin to develop
Passive carrier is someone like a healthcare provider contaminated with the pathogen and transfers them to other patients
A live animal other than human that transmits an infectious agent from one host to another is called a ________
Vector
What are direct and indirect contact methods of transmission?
Direct:
- kissing, sexual contact
- respiratory droplets
- vertical (mother to child)
- Biological vector
Indirect:
- fomites are contaminated
- Food, water, biological products
- airborne microbes
- aerosols: airborne animal wastes (Hantavirus from rats)
What is a fomite?
Any inanimate object we can come into contact with
What are communicable and non-communicable diseases? Give an example of each.
Communicable: When an infected host can transmit the infectious agent to another host and establish infection in that host
eg. influenza, aids
Non-communicable: Occurs primarily when a compromised person is invaded by their own normal microflora
eg. E.coli, cancer
Where are nosocomial infections acquired?
In healthcare settings from surgical procedures, equipment, personnel, and exposure to drug-resistant microorganisms
