Chapter 15 Flashcards
mechanisms ways in which the body protects itself from pathogens—can be thought of as an army consisting of three lines of defense
Host defense mechanisms
these are ways in which the body attempts to destroy all types of substances that are foreign to it,
including pathogens.
first two lines of de-
fense are nonspecific;
what line of defense wherein special
proteins called antibodies are usually produced in the body in response to the presence of foreign substances.
third line of defense
they stimulate the production of specific antibodies; they are
“antibody-generating” substances.
antigens
mechanisms are general and serve to protect the body against many harmful sub-
stances.
Nonspecific host defense mechanisms
serve as nonspecific host
defense mechanisms by
serving as physical or
mechanical barriers to
pathogens.
skin and mucous
membranes
serves as a nonspecific host defense mechanism by flushing organisms from pores and the surface of the
skin.
Perspiration
Perspiration also contains the enzyme, ____
which degrades peptidoglycan in bacterial cell walls
lysozyme
is a protein that binds iron, a mineral that is required by all pathogens.
Lactoferrin
is an enzyme that produces superoxide radicals, highly reactive forms of oxygen, which are toxic to bacteria.
Lactoperoxidase
these are present on epithelial cells of the posterior nasal membranes, nasal sinuses, sweep the trapped dust and microbes upward toward the throat,
cilia (mucociliary covering)
which is secreted
from the liver into the small
intestine, lowers the surface
tension and causes chemical
changes in bacterial cell walls
and membranes that make
bacteria easier to digest.
Bile,
serve to remove
pathogens from the GI
tract and urinary tract,
respectively.
Peristalsis and urination
a glycoprotein
synthesized in the liver, has a high affinity for iron. Its normal function is to store and deliver iron to host cells.
Transferrin,
A body temperature
greater than ___ is a fever
37.8
Substances that stimulate the production of fever are called
pyrogens or pyrogenic
substances.
Some bacteria produce proteins that kill other bacteria;
collectively, these antibacterial
substances are known as
bacteriocins.
are small,
antiviral proteins
produced by
virus-infected cells.
They interfere with
viral replication.
Interferons
b interferon is produced by
fibroblast