Hydropic Change
Cellular swelling occurs when ischemia causes ATP depletion and the loss of membrane ion pumps, resulting in the movement of water into cells. It is a form of
reversible
injury.
Adaptation
Reversible
changes in the size, number, phenotype, or function of cells in response to stimuli (e.g. hormonal or neural) or injury.
Hypertrophy
Increase in the size of cells
Hyperplasia
Increase in the number of cells
Atrophy
Decrease in the size or number of cells
Metaplasia
Reversible
change from on differentiated cell to to another.
Barrett esophagus
Intestinal metaplasia of the esophageal squamous epithelium in response to gastric (acid) reflux.
Steatosis
A
reversible
accumulation of triglycerides in cells (particularly hepatocytes) as a result metabolic dysfunction.
Hemosiderin
A hemoglobin derived pigment that is deposited when red blood cells are digested by macrophages.
Dystrophic calcification
The deposition of calcium phosphate in areas of necrosis or chronic cellular injury.
Pyknosis
Irreversible
condensation of chromatin in the nucleus
Karyorrhexis
The
irreversible
destructive fragmentation of the nucleus of a necrotic cell.
Karyolysis
The complete dissolution of the nucleus of a cell (
irreversible
).
Apoptosis
"Programmed" cell death induced by the activation of a suicide pathway. In contrast to necrosis, it usually occurs with single cells that are ultimately resorbed, and does not elicit an inflammatory response.
Intrinsic apoptosis
Self-induced apoptosis occurring via the Bcl-2 and mitochondrial suicide pathways.
Extrinsic apoptosis
Induction of apoptosis by the activation of membrane bound death receptors.
Acidophil body
An eosinophilic apoptotic hepatocyte frequently seen in viral hepatitis.
Mallory Body
An eosinophilic, intracytoplasmic inclusion containing cytokeratin and ubiquitin frequently seen in alcoholic liver disease
Necrosis
The death of cells resulting from, for example, loss of blood supply, bacterial toxins, or physical or chemical agents. Subdivided into caseous, coagulative, liquefactive, gangrenous, fat, and fibrinoid (we define these in subsequent labs).
Gangrenous necrosis
Necrotic tissue acted upon by bacteria. "wet" and "dry" types.
Edema
The abnormal accumulation of interstitial (extravascular) fluid.
Transudate
Fluid that escapes the vasculature because of disturbances of hydrostatic or colloid osmotic pressure.
Exudate
Fluid that that escapes the vasculature because of inflammation.
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