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26 Cards in this Set

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what are a cells responses to an injurious stimulus
if its reversible cell injury it has not passed the point of irreversibility, however, if not treated, can lead to necrosis. if the injury sustained is bad enough, the cell could just enter apoptosis
differentiate hypoxemia and hypoxia
-hypoxemia is low levels of oxygen in blood (ex. anemia)
-hypoxia is low levels of oxygen in tissues
what are characteristics of cell injury
1. integrity of cell membranes
2. aerobic respiration - oxidative phosphorylation and ATP
3. synthesis of enzymes & proteins
4. preservation of genetic apparatus of the cell
define ischemia. anoxia
insufficient blood supply bc occlusion of artery or vein.
-total loss of oxygen supply
what are the two types of morphology in injured cells
swells bc of Na+ channel into cell.
1. reversible injury - cell swelling leading to hydropic change or vacuolar degeneration
2. irreversible injury - cell injury leading to necrosis (nuclear pyknosis [condensation of chromatin] followed by karyorrhexis and karyolysis [dissolves away])
is irreversible if there is a rupture of cell membrane or lysosomes
what are the ultrastructural features of cell injury?
1. cell swelling
2. cytoplasmic blebs
3. distortion of microvilli
4. mitochondrial swelling
5. dilatation of ER
define karyorrhexis
Rupture of the nucleus, releasing disintegrated chromatin.
list the types of necrosis
1. coagulative
2. liquefaction
3. fat
4. caseous
5. fibrinoid
6. gangrenous
define coagulative necresis and what can cause it?
-dissolution of nucleus with preservation cellular shape and tissue architecture.
-ischemic injury, ionizing radiation, viruses, chemicals
- coagulation (denaturation) of cell proteins
define: autophagy
Digestion of the cell's own organelles
define: liquefaction necrosis, and give ex.
hydrolytic enzymes cause autolysis and heterolysis. ex. abscess (often in lung)and brain infarct (stroke)
define: fat necrosis, and give ex.
destruction of adipose tissue due to action of lipases. ex. pancreatitis, pancreatic tumor, salivary gland (trauma or infection), breast (trauma).
with coagulative necrosis in the kidney, what order will the areas be damaged by ischemia
1. PCT
2. glomeruli
3. collecting duct
define: caseous necrosis
combination of coagulative and liquefaction necrosis. primarily foudn in the center of tubercles. inability to digest and remove material from center of granuloma. sharp border btw granuloma. cottage cheese consistency, ex tb in lungs
define: fibrinoid necrosis
necrotic tissue due to immunologic reaction. usu seen in blood vessels with deposition of complement and antibodies in vessel wall. seen as bright red in stain indicating dead tissue, complement and Ab.
define: gangrenous necrosis
coagulative necrosis with secondary bacteria infection leading to liquefaction.
differentiate wet and dry gangrene
dry - coagulative necrosis is the predominant pattern
wet - liquefactive process is the dominant pattern.
define apoptosis
programmed cell death
give ex. of physiologic apoptosis
1. embryogenesis (loss webbed fingers)
2. hormone-dependent involution - menstrual cycle, lactating breast
3. deletion of proliferating cells - intestinal crypt epithelia
4. selective death of immunocytes - developing thymus
give ex. of pathologic apoptosis
1. viral dx leading to cell death (acidophil or councilman bodies, viral hepatitis)
2. pathologic atrophy - prostatic atrophy after castration
3. duct obstruction - cells self destruct
4. T8 (cytotoxic) lymphocytes - graft-versus-host dx
5. injurious agents - anticancer drugs, radiation
mechanisms of apoptosis
1. activation of endonucleases
2. cytoskeleton disruption by proteases
3. cytoplasmic protein cross-linking by transglutaminase
4. cell surface changes leading to phagocytosis
compare morphologic characteristics of apoptosis to necrosis
A - general cell shrinkage, chromatin condensation, bleb formation & apoptotic bodies, phagocytosis, and lack of an inflammatory reaction
N - swelling cells, water, chromatin condensation, blebs, then blow up, inflammatory reaction clean up mess
two pathologic techniques to determine if cell is undergoing apoptosis or necrosis
1. histo stain - apoptotic bodies have no inflammatory rxn around them, as compared to a necrotic breakdown.
2. run DNA ladder with endonucleases - if apoptosis, you will see specific sites with endonucleases, whereas with necrosis, you will see a smear of dif size DNA pieces.
intracellular accumulations can occur with which compounds?
lipids, proteins, glycogen, complex lipids and carbohydrates, and pigments
what types of fatty change can occur?
histologically - push nucleus to side, and stain red
1. lipid in parenchyma cells (ex. alcoholic fatty liver)
2. lipid in macrophages (ex. xanthomas, foam cells)
3. stromal infiltration of fat (ex. fat in myocardium)
give examples of exogenous and endogenous pigments
exogenous: carbon (anthracosis), tattooing, natural substances (B carotene), poisons - lead (pica)
endogenous pigments - lipofuscin, melanin, hemosiderin