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
alpha interferons are produced by
B lymphocytes
gamma interferon is produced by
T lymphocytes
Interferons are not
virus-specific, but they
are
host-specific.
a group of
approximately 30 different pro-
teins (including nine proteins
designated as C1 through C9)
that are found in normal blood
plasma. to the action of
the immune system.
Complement system
a process by which phagocytosis is facilitated by the deposition of opsonins, such as antibodies or
certain complement fragments onto the surface of particles or
cells.
Opsonization
these proteins increase rapidly in response to infection, inflammation, and tissue injury. They serve as host defense mechanisms by enhancing resistance to infection and promoting the repair of damaged tissue.
Acute phase proteins
are chemical mediators that are released from many different types of cells in the human body.
cytokines
They enable cells to communicate
with each other. They act as chemical messengers both within the immune system
cytokines
3 major events in inflammation
vasodilation
increased permeability of capillaries
escape of leukocytes from capillaries
chemotaxis
phagocytosis
The accumulation of fluid,
cells, and cellular debris at the inflammation site is referred to
as an
inflammatory exudate.
If the exudate is thick and greenish yellow, containing many
live and dead leukocytes, it is known as a
a purulent exu-
date or pus.
The three major
categories of leukocytes
found in blood
monocytes,
lymphocytes, and
granulocytes.
two most important groups of phagocytes in the human body are
macrophages
and neutrophils;
3 types of granulocytes
basophils, eosinophils,
and neutrophils.
Macrophages are extremely efficient phagocytes.
They are found in tissues of the
reticuloendothelial
system (RES).
The four steps in phagocytosis are
chemotaxis,attachment, ingestion, and digestion.
phagocytes move to the site
where they are needed. This
directed migration is called
chemotaxis
a digestive vacuole within which killing
and digestion occur
phagolysosome
Some
bacteria produce an exoenzyme (referred to as a toxin by some scientists) called ____which kills phagocytes.
Leukocidins
an abnormally low number
of circulating
leukocytes.
Leukopenia
Which of the following is not part of the body’s first
line of defense?
a. fever
b. intact skin
c. mucus
d. pH of the stomach contents
a
Each of the following is considered a part of the
body’s second line of defense except:
a. fever.
b. inflammation.
c. interferons.
d. lysozyme.
d
Which of the following is not a consequence of acti-
vation of the complement system?
a. attraction and activation of leukocytes
b. increased phagocytosis by phagocytic cells
(opsonization)
c. lysis of bacteria and other foreign cells
d. repair of damaged tissue
d
Each of the following is a primary purpose of the
inflammatory response except:
a. to localize the infection.
b. to neutralize any toxins being produced at the
site.
c. to prevent the spread of microbial invaders.
d. to stimulate the production of opsonins.
d
Which of the following cells is a granulocyte?
a. eosinophil
b. lymphocyte
c. macrophage
d. monocyte
a
All the following would be considered an aspect of
microbial antagonism except:
a. competition for nutrients.
b. competition for space.
c. production of bacteriocins.
d. production of lysozyme.
d
Which of the following function as opsonins?
a. antibodies
b. antigens
c. complement fragments
d. both a and c
d
Which of the following statements about interferons
is false?
a. Interferons are virus-specific.
b. Interferons have been used to treat hepatitis C
and certain types of cancer.
c. Interferons produced by a virus-infected cell will
not save that cell from destruction.
d. Interferons produced by virus-infected rabbit cells
cannot be used to treat viral diseases in humans.
a
Which of the following is not one of the four cardi-
nal signs or symptoms of inflammation?
a. edema
b. heat
c. loss of function
d. redness
c
