The Immune System I Flashcards
(60 cards)
The body has three lines of defense against attack by foreign invaders: _____, _____ and
_____.
non-specific barriers; non-specific defenses; specific defenses
The skin is an example of a(n) _____. Physically, the outer layer is highly-cross-linked
keratin and is waterproof, blocking many invaders and their toxins.
non-specific barrier
Invaders not only have difficulty penetrating the skin’s structure, they are also repelled or
destroyed by the skin’s _____
acidic secretions
. Tears, saliva, and other secretions include lysozyme which _____.
breaks down bacterial walls
Mucous membranes and the cells that line them serve as a(n) _____: invaders become
trapped in the mucous and are swept out by _____.
non-specific barrier; ciliated
cells
Most microbes living in the food (or drink) which we ingest are destroyed by _____ before
they can cross into the body: this is a(n) _____.
gastric juices; non-specific
barrier
_____ are found on many bodily surfaces; they remove nutrients and other materials that
would otherwise be available to pathogenic species.
Symbiotic bacteria
The second line of defense in the immune system uses _____ to attack a(n) _____
invader.
chemical and cellular methods;
unrecognized
Lymphocytes which mature in the lymph system (as opposed to in the marrow or thymus)
are called _____, and are a part of the non-specific defense system.
natural killer (NK) cells
_____ recognize cells whose surface markers are drastically “non-self” - missing major
markers or containing non-human glycoproteins - and kill them. (They [are/are not?]
phagocytic.)
NK cells; are not
Neutrophils and macrophages ingest _____, and so play a role in non-specific defenses.
foreign material and debris
Macrophages sometimes kill their prey with chemicals including peroxide and bleach in a
process called _____.
the respiratory burst
A set of about 20 proteins present in the blood that, when activated, bind to pathogens
and both _____ and _____ are called “complement.”
attract phagocytes; disrupt the
pathogen’s membranes
In the “classical pathway” for complement activation, complement proteins recognize
_____.
antibodies bound to antigens
In the “alternative pathway” for complement activation, complement proteins recognize
_____.
polysaccharides on a
microorganism’s surface
“Viral infections” are infections in which viral _____ enter the cell, and the cell is forced to
make _____ instead of, or in addition to, its own.
nucleic acids; viral proteins
Many cells, after being infected by a virus, manage to secrete _____ which stimulate
neighboring cells to resist viral infection and ultimately signal the immune system.
interferons (IFNs)
_____ is a systemic response in which cellular metabolism is accelerated and which
creates a hostile environment to the invader: the danger is that, if excessive, it may also
damage host tissue.
Fever
The four signs of acute inflammation are _____, _____, _____, and _____.
redness; heat; swelling; pain
The inflammatory response is a(n) _____.
non-specific defense
The inflammatory response is initiated when _____ and nearby circulating cells.
chemicals are released by
injured cells
Vasodilation increases _____ and causes redness and heat.
blood flow
Increased _____ causes local edema; this in turn causes swelling and pain.
capillary permeability
Increased capillary permeability allows clotting factors to leak into the interstitial fluid: as a
result _____.
pathogens become trapped in
the resulting fibrin mesh
