Immune Defense Mechanisms Flashcards
refers to the mechanisms of defense that we are born with, while “nonspecific” means that they include defenses against ANY pathogen - whether we have encountered it before or not
INATE IMMUNITY
involves defenses against specific invading agents and may involve responses against something that we have encountered previously
ADAPTIVE IMMUNITY
Examples of innate immune mechaisms
physical barriers
mechanical removal
chemical measures
antimicrobial substances
cells
inflammation
fever
phagocytes:
and include:
ingest and destroy microbes or particles such as cellular debris
include: NEUTROPHILS AND MACROPHAGES
5 STEPS OF PHAGOCYTOSIS
CHEMOTAXIS
ADERENCE
INGESTION
DIGESTION
KILLING
CHEMOTAXIS
chemicals from damaged cells, tissue macrophages, and microbes attract phagocytes to the affected area
ADHERENCE
phagocytes attach to the microbe, which may be enhanced by complement proteins
INGESTION
extensions of the plasma membrane of the phagocyte engulf the microbe, meet and fuse into a sac known as a phagosome
DIGESTION
the phagosome merges with lysosomes to form a phagolysosome
enzymes and oxidants break down the microbe
KILLING
the microbe is destroyed by the actions of the enzymes and oxidants
these kind of cells make up about 5-10% of the lymphocytes in the blood and act non-specifically against our own cells that have been infected or against some tumor
NATURAL KILLER (NK) CELLS
NK CELLS bind to
body cells that display abnormal plasma membrane proteins
4 characteristics of inflammation
redness
pain
heat
swelling
THREE BASIC STAGES OF INFLAMMATION
- vasodilation and increased permeability of blood vessels
- emigration of phagocytes to the affected area and movement into tissue
- tissue repair
among the substances that tigger VASODILATION AND INCREASED PERMEABILITY are:
histamine
kinin
prostaglandins
leukotrienes
complement
As blood flows into the affected area due to vasodilation, the accumulation of RBC’s leads to _____ of the area
REDNESS
_____ carried by the blood makes the area warmer, which may make some defensive chemical reactions proceed more quickly and produce even more ____
HEAT
______ is triggered by damage to neurons, pressure on nociceptors due to fluid accumulation in tissues (edema), and chemicals such as kinins, prostaglandins, or toxins released from microbes
PAIN
_____ is due to the movement of formed elements and plasma proteins from the blood into tissues and subsequent movement of water via osmosis
SWELLING
where in the body would the temperature be “set” to a higher level?
HYPOTHALAMUS - the thermostat of the body
substances that are recognized as foreign and provoke immune responses are known as _____, which means that they provoke the body to produce ______
ANTIGENS;
antibodies
adaptive responses include
SPECIFICITY
MEMORY
B AND T CELL involvement
antigens that get past innate defenses like the skin tend to encounter lymphocytes in one of three places:
SPLEEN -in blood
LYMPH NODES - enter tissues or lymphatic vessels
MALT - if they penetrate mucous membranes
located on your cells are ____ _____ that identify your cells as self
SELF-ANTIGENS
AUTOIMMUNE
tolerance of our cells may break down and our immune defenses may attack healthy cells
both B and T lymphocytes assume ___ ____ when they encounter the antigen to which they are specifically designed
ACTIVE FORMS
ACTIVE FORM OF B CELLS
PLASMA CELLS
PLASMA CELLS
PRODUCE ANTIBODIES which then act on pathogens
ANTIBODY-MEDIATED IMMUNITY
TWO ACTIVE FORMS OF T CELLS
CYTOTOXIC T CELLS
HELPER T CELLS
CYTOTOXIC T CELLS
produce chemicals that directly attack invading antigens
CELL-MEDIATED IMMUNITY
- capable of destroying specific antigens by using destructive enzymes (like NK cells, but specific)
HELPER T CELLS
utilize chemicals that assist both antibody-mediated and cell-mediated responses
*use chemicals to assist many other defense mechanisms
once _____ _____ occurs, thousands of lymphocytes can recognize the antigen on subsequent exposures
CLONAL SELECATION
ANTIBODIES DO NOT DESTROY FOREIGN ANTIGENS, but
disable antigens by various mechanisms
antibodies disable antigens by various mechanisms including:
neutralization
agglutination or precipitation
activating complement-antibody-antigen
enhanced phagocytosis
Neutralizing antigens
they NEUTRALIZE some bacterial antigens or prevent some viruses from attaching to body cells
AGGLUTINATION OR PRECIPITATION of antigens
antibodies may “clump” antigens to each other
-ANTIBODY-ANTIGEN
completes may trigger complement defenses
ENHANCED PHAGOCYTOSIS
attraction of phagocytes by various means
MEMORY CELLS
remember the antigen and may trigger immune responses very quickly on subsequent exposures to the same antigen
ANTIBODY-MEDIATED DEFENSES are especially effective against
EXTRACELLULAR PATHOGENS - bacteria, viruses, or fungi in body fluids outside of body cells
CELL-MEDIATED DEFENSES tend to be more effective against
PATHOGENS INSIDE OUR BODY CELLS, some cancer cells, and translated foreign tissues
many antigens trigger both
antibody-mediated and cell-mediated responses
INNATE IMMUNITY may be determined by several different mechanisms:
SPECIES
ANCESTRAL
INDIVIDUAL
ACQUIRED IMMUNITY may be due to
exposure to a pathogen or an antibody
4 WAYS TO ACQUIRE IMMUNITY
naturally acquired active
naturally acquired passive
artificially acquired active
artificially acquired acpassive
NATURALLY ACQUIRED ACTIVE
encounter the pathogen by natural means
NATURALLY ACQUIRED PASSIVE
“Borrow” antibodies, manually (breast milk, across the placenta
ARTIFICIALLY ACQUIRED ACTIVE
receive an injection or other introduction of pathogens
ARTIFICIALLY ACQUIRED PASSIVE
receive an injection of antibodies
