chapter 12 Flashcards
(56 cards)
What is the sterile environment crucial for during early development?
Maintaining a sterile environment in utero
This ensures the human body is free of microbes during development.
When does a newborn’s first exposure to microbes occur?
During the birth process
This exposure starts the colonization of the infant’s intestine and skin.
What is mutualism in symbiotic relationships?
A relationship where both organisms benefit
Example: Bacteria in the human gut aiding digestion while receiving nutrients.
Define commensalism.
A relationship where one organism benefits and the other is neither harmed nor helped
Example: Skin bacteria feeding on dead cells.
What is parasitism?
A relationship where one organism benefits at the expense of the other, causing harm
Example: Pathogens causing diseases in their hosts.
What is amensalism?
One organism inhibits the growth or survival of another without being affected
Example: Antibiotic production by certain bacteria.
What initiates the colonization process in newborns?
Initial contact with microbes in the birth canal
This is the first step in establishing normal flora.
What are resident flora?
Microbes that remain part of the normal flora throughout a person’s life
They continually inhabit specific body sites.
What are transient flora?
Microbes that are temporarily found in the same locations as resident flora
They persist for hours, days, or months before disappearing.
What can cause normal flora to become opportunistic pathogens?
Disruption of the balance between normal flora and the human host
This can lead to infections.
What is the first stage of infection?
Contamination
This is the presence of microbes in or on the body.
What occurs during an infection?
A microorganism gains entry into the host and its tissues, potentially causing disease
This is a critical transition from contamination.
What are portals of entry?
Specific sites where pathogens enter the body
They facilitate infection.
What is the role of the skin as a portal of entry?
Acts as a barrier against pathogens
Pathogens can enter through natural openings or damage.
What types of bacteria are included in enteric bacteria?
- Salmonella
- Shigella
- Vibrio
- Certain strains of E. coli
These bacteria cause infections through the gastrointestinal tract.
What is the most frequently used portal of entry for pathogens?
Respiratory tract
This leads to respiratory infections.
What is the parenteral route?
A method that bypasses normal entry routes, directly introducing pathogens to subcutaneous tissue
Examples include punctures and cuts.
Define virulence.
The degree of pathogenicity or disease-provoking power of a specific microbe
It determines the severity of infection.
What are virulence factors?
Traits that enhance a microbe’s ability to cause disease
They are crucial for understanding virulence.
What is adhesion in the context of microbial infection?
The first step of infection, enabling pathogens to attach to host cells and tissues
Without adhesion, organisms can be removed by various bodily functions.
What is colonization?
The establishment of a foothold by pathogens in tissues that are in contact with the external environment
Common sites include the urogenital tract, digestive tract, respiratory tract, and conjunctiva.
What are invasins?
Extracellular substances produced by pathogens that facilitate their spread and establishment within host tissues
They disrupt host cell membranes.
What are toxins in the context of microbial pathogenesis?
Harmful substances produced by organisms that can cause disease
An organism that produces toxins is termed toxigenic.
What defines exotoxins?
Proteins released by bacteria during the exponential growth phase
They can act at remote sites from the infection location.
