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24 Cards in this Set
- Front
- Back
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What are the 4 major types of cellular adaptations?
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Atrophy, hypertropy, hyperplasia, metaplasia
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What are the general causes of cellular adaptations?
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Physiologic; responses to normal processes. Pathologic; regulated response to normal signals in pathologic situations
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What is atrophy?
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Shrinkage in the size of a cell by loss of cell substance. Shrinkage in size of organ due to cell atrophy
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What are the causes of atrophy?
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Dec work load, innervation loss, diminished blood supply, inadequate nutrition, loss of endocrine stim, & aging
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What are the biochemical mech of atrophy?
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Dec synthesis, inc catabolism, both
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What are the histologic changes of atrophy?
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Dec cell size, inc autophagic vacuoles, inc residual bodies (lipofuscin)
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What is hypertrophy?
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In size of cells & inc size of organ. Prominent in organs w/ cells incapable of mitosis. Inc synthesis of structural proteins & nuclear DNA. Inc organelles
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What are the types of hypertrophy?
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Physiologic; skeletal muscle w/ exercise & uterine smooth muscle. Pathologic; myocardium in hypertension
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What are the causes of hypertropy?
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Inc functional demand; skeletal m. in exercise & myocardium in hypertension. Specific hormonal stim; uterus in pregnancy
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What is hyperplasia?
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Inc in # of cells in an organ or tissue. Often occurs w/ hypertrophy.
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What are the physiologic types of hyperplasia?
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Hormonal; breast during pregnancy. Compensatory; partial hepatectomy.
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What are the mech of compensatory hyperplasia?
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Proliferation of existing cells (eg partial hepatectomy w/ fcnal hepatocytes). Formation of new cells from stem cells (eg hepatocellular injury & cell loss). Pathologic (eg excessive hormonal/GF, response to injury/inflammation)
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What is metaplasia?
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A reversible change in which 1 adult cell type is replaced by another adult cell type. Genetic reprograming of stem cells (epithelial or mesenchymal)
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What are the types of metaplasia?
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Squamous; respiratory epi from smoking or vit A deficiency. Gastric; lower esophageal epi from chronic reflux. Mesenchymal; not clearly an adaptive response (fibroblasts transform into osteo or chrondroblasts)
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What is necrosis?
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Sequence or morphologic changes that follow cell death in living tissue.
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What are the general mech of necrosis?
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Enzymatic digestion of cell (autolysis & heterolysis) & denaturation of proteins
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What are the types of necrosis?
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Coagulative, liquifactive, fat, fibrinoid, & gangrenous
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What is coagulative necrosis?
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Immediate denaturation, preservation of structural outlines for days, charac of hypoxic cell death except in the brain
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What is liquifactive necrosis?
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Complete digestion of dead cells. Charac of bacterial & some fungal infections, & hypoxic death in the CNS
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What is caseous necrosis?
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Cheesy, white gross appearance, amorphous granular debris in a ring of granulomatous infection. Charac of tuberculous infection
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What is fat necrosis?
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White, chalky areas grossly. Shadowy outlines of necrotic fat cells w/ basophilic calcium deposits (saponification)- due to pancreatic lipase action.
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What is fibrinoid necrosis?
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Vascular lesion, hyaline appearnace in arterial media. Cause is immune mediated. Hyaline appearance is due to fibrin plus antigen/antibody complexes
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What is gangrenous necrosis?
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Not a specific pattern, usually refers to necrosis in a limb that loss blood supply
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What are the types of gangrene?
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Dry: coagulative necrosis & Wet: infection may lead to liquifactive necrosis. Maybe seen in diabetes.
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