Final: Chapter 13- Microbe/human Interactions Flashcards
What is the approximate ratio (current) of microbes to human cells in and on the human body?
1:1 ratio
What are normal biota?
Bacteria that are normally found on the human body
What is microbial antagonism and what are the two general mechanisms of microbial antagonism?
Microbial antagonism refers to the inhibitory effect that normal biota have on other “invading” microbes.
Mechanisms= blocking body sites that could be established by “invaders”, and releasing chemicals that are harmful to invading microbes
What is the difference between and opportunistic and primary (truth) pathogen?
Opportunistic= cause disease when the host’s immune system is compromised
Primary (true)= capable of causing disease in healthy people with normal immune functions
What is microbial virulence and how is it determined (2 things)?
Microbial virulence is the degree of pathogenicity an organism exhibits
Determined by: the ability to establish in the host, and the ability to cause damage to the host
What are portals of entry?
Routes of entry in the human body. Include the skin and mucous membranes, gastrointestinal tract, respiratory tract, and urogenital tract.
What does the term infectious dose indicate about a microbes?
And infectious dose is the number of microbes needed to cause infection. Microbes with a SMALL infectious dose are MORE virulent. Microbes with a LARGE infectious dose are LESS virulent.
What is the difference between direct and indirect damage, resulting from pathogens?
Indirect damage happens when the immune system tries to damage a pathogen, but in the process causes harm or discomfort to the host. While direct damage directly affects the pathogens it is trying to destroy.
What are the 4 stages of infection?
Localized infection= microbe enters the body and remains confined to a specific tissue
Systemic infection= microbe spreads to several sites and tissue fluids, usually in the bloodstream
Focal infection= microbes break loose from a local infection and it carried into other nearby tissues
Toxemia= infection remains localized at portal of entry, but toxins produced by pathogen are carried to the target organ
What is the difference between a mechanical vector and a biological vector?
Mechanical vector= not a necessary component of a pathogen’s life cycle, but they may transfer the pathogen without being infected
Biological vector= actively participate in the life cycle of the pathogen they transmit and are usually necessary for the pathogen to complete its life cycle
What are zoonotic pathogens?
Pathogens that are harbored or vectored by animals and are transmissible to humans
