CPA #17 Questions Flashcards
Define: phagocytosis
“eating of a cell”; a way some microbes obtain nutrients; phagocytes use this to rid the body of pathogens to protect the body
what are the 6 steps of phagocytosis?
- chemotaxis
- adhesion
- ingestion
- maturation
- killing
- elimination
define: chemotaxis
movement of a cell either toward or away from a chemical stimulus (toward = positive; away = negative)
define: adhesion (phagocytosis)
at site of infection; phagocytes attach to microorganisms through binding of complementary chemicals; pathogens are more readily phagocytized if they are covered with antimicrobial proteins (opsonins)
define: opsonins
antimicrobial proteins that cover the pathogen allowing for phagocytosis
define: opsonization
the process of covering pathogens with antimicrobial proteins
define: ingestion (phagocytosis)
after adhering to pathogens, phagocytes extend pseudopods to surround microbe; pseudopods fuse together to form food vesicle (phagosome)
define: maturation (phagocytosis)
lysosome adds digestive chemicals to the maturing phagosome (phagolysosome)
define: phagolysosome
contain antimicrobial substances & 30+ different enzymes to destroy the engulfed microbes
define: killing (phagocytosis)
phagolysosome kills the engulfed microbe
define: elimination (phagocytosis)
phagocytes eliminate the remaining portions of microbe via exocytosis
define: eosinophilia
abnormally high number of eosinophils in the blood (typically from helminth infestation or allergies)
unusual action that eosinophils can perform
lipopolysaccharide from Gram- bacteria trigger eosinophils to rapidly eject mitochondrial DNA to combine with eosinophil proteins to create a barrier; this barrier binds to and kills the bacteria
define: NK cells
natural killer lymphocytes; defensive leukocyte; innate immunity
explain NK cell function
secretes toxins onto surfaces of virally infected cells and neoplasms (tumors); identify and spare normal body cells due to similarities with the proteins of NK cells; naturally programmed to kill other cells
define: neutrophil NETs
neutrophil extracellular traps; extracellular fibers; cellular suicide involving disintegration of own nuclei
how can neutrophils kill by forming NETs
as the neutrophil cell dies, the NETs are released, trapping Gram- & Gram+ bacteria along with antimicrobial peptides, killing the bacteria
define: inflammation
general, non-specific response to tissue damage resulting from a variety of causes, including heat, chemicals, UV, pathogens, etc.
define: acute inflammation
develops quickly, short lived, typically beneficial, and results in the elimination of whatever condition caused it (helpful)
define: chronic inflammation
causes damage, sometimes death, to tissues, resulting in disease (harmful)
what are the 4 signs and symptoms of inflammation?
- redness (rubor)
- localized heat (calor)
- edema (swelling)
- pain (dolor)
define: vasodilation
increase in diameter of blood vessels in affected region
which s+s of inflammation is vasodilation involved in?
all 4; increased dilation causes the redness + local heat; the increased permeability of venules can lead to increased fluid in surrounding tissues, causing edema + pain
what chemical causes vasodilation of arterioles?
histamine
what cells secrete histamine?
basophils, platelets, and mast cells
define: fever
body temp above normal (above 37C)
what controls fever?
hypothalamus
what chemicals are secreted that affect fever?
pyrogens
define: pyrogens
chemicals that trigger the hypothalamus to reset at a higher temp; include bacterial toxins, antibody-antigen complexes
why do chills occur with fever?
as the fever progresses, blood vessels on the skin constrict (vasoconstriction); less blood to the skin causes them to feel cold to the touch and less red
define: antigen
portions of of cells, viruses, and parts of single molecules that the body recognizes as foreign and worthy of attack; biochemical shapes
define: epitopes
the 3D shape of a region of an antigen; determine the immune response caused; aka antigenic determinants
what are the 3 types of antigens?
- exogenous antigens
- endogenous antigens
- autoantigens
define: exogenous antigens
come from outside the body’s cells and include toxins and other secretions/components of microbial cell walls, membranes, etc.
define: endogenous antigens
produced by protozoa, fungi, bacteria, and viruses that reproduce inside a body’s cells; the immune system cannot assess the internal health of the body’s cells; only responds when the antigens are incorporated into cytoplasmic membrane
define: autoantigens
derived from normal cellular processes; aka self-antigens
define: self-tolerance
process of eliminating immune cells that attack autoantigens; which prevents the body from starting an immune response against itself
define: antibodies
free immunoglobulins (not attached to a membrane); ‘Y’ shaped; bind with antigens
define: agglutination
multiple antibodies can aggregate antigens together
define: ABO system
two antigens (‘A’ and ‘B’); RBCs have either A/B, A+B, or neither (‘O’)
define: transfusion reactions
the blood recipients own immune system attacks the donor blood; the donor blood triggers the reaction
define: hemolysis
rupturing of blood cells; can occur during a transfusion reaction
define: Rh antigen
on outside of blood cell, either +/- ; 85% of population is Rh+ and 15% is Rh-
define: RhoGAM
anti-Rh immunoglobulin (IgG) which destroys the fetal cells before they can trigger an immune response
define: hemolytic disease of newborn
Rh- mother is pregnant with Rh+ baby; fetal blood cells escape into mothers bloodstream and trigger immune response
