C15 Flashcards
Ways in which the body protects itself from
pathogens—referred to as three lines of defense.
Host defense mechanism
are general and serve to protect the body against many harmful substances.
Ex. Innate or inborn
Nonspecific host defense mechanisms
In addition to the skin as a. physical barrier, there are other factors (e.g., pH and temperature of skin, perspiration, cilia, and various enzymes in secretions such
as lysozyme) that are components of the first line of defense.
Cellular and chemical factors
When indigenous microbiota prevent colonization of “new arrivals” as a result of competition for sites and nutrients
and production of lethal substances
Microbial antagonism
Levels of this glycoprotein increase in response to systemic bacterial infections; it binds to iron depriving pathogens of this vital nutrient.
Transferrin
Stimulated by pyrogenic (fever-producing)
substances (e.g., pathogens and interleukin
Fever
These are small antiviral proteins produced by virus-infected cells; they prevent viruses from multiplying.
Interferons
Three types of interferron
Alpha gamma beta ( produced by three different types of cell)
Interferons are not virus-specific, but they are
species-specific.
is a process by which phagocytosis is
facilitated by the deposition of opsonins (e.g., antibodies or certain complement fragments) onto objects (e.g., pathogens).
Opsonization
Complement components interact with each other in a stepwise manner known as the
Complement cascade
Plasma proteins that increase rapidly in response to infection, inflammation, or tissue injury; (e.g., is C-reactive protein).
Acute phase protein
These are chemical mediators released from many different types of cells in the body; they enable cells to communicate with each other—within the immune system and between the immune system and other systems of the body.
Cytokines
The body responds to any local injury, irritation, microbial invasion, or bacterial toxin by a complex series of events referred to as
inflammation;
The primary purposes of the inflammatory response are to
– Localize an infection
– Prevent the spread of microbial invaders
– Neutralize any toxins being produced at the site
– Aid in the repair of damaged tissue
