cellular adaptations dr. peter anderson, uab pathology
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Cellular AdaptationsEnvironmental Factors
• Increased or decreased stimulation• Increased or decreased work• Decreased blood flow • Abnormal materials
Normal Cells
Atrophy
Hypertrophy
Hyperplasia
Metaplasia
Dysplasia
Response to Stress
Copyright © 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved
Atrophy
• Shrinkage in the size of the cell by loss of structural components– Decreased work load– Loss of innervation– Diminished blood supply– Inadequate nutrition – Loss of endocrine stimulation
Hypertrophy
• Increased size of cells & the organ• Physiologic
– Hormonal stimulation e.g., uterus during pregnancy
• Pathologic– Increased functional demand e.g., Left
Ventricular Hypertrophy (LVH) - hypertension or valve stenosis
Hyperplasia
• Increase in the number of cells in an organ or tissue– Physiologic hyperplasia
• hormonal induced – breast in pregnancy– Pathologic hyperplasia
• viral induced – papillomaviruses• excessive hormonal stimulation - prostate
Metaplasia• Reversible change in which one differentiated cell
type is replaced by another cell type.
Ciliated Columnar Epithelium
Squamous epithelium
Metaplasia Summary
• Reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type
Intracellular Accumulations
• Lipids• Proteins• Glycogen• Carbohydrates
• Carbon• Silica• Asbestos• Bacteria
Normal CellularConstituents
Abnormal or Exogenous
Fatty Change
• Lipid in macrophages– foam cells - atherosclerosis
• Lipid in parenchyma cells– alcoholic fatty liver
Intracellular Proteins
• Kidney Proximal Tubules– hyaline droplets
• Plasma Cells– Russell bodies
• Alcoholic Hyaline
• Liver cells of alcoholics• Tangled skeins of cytokeratin intermediate
filaments and other proteins• Eosinophilic cytoplasmic inclusions• Called Mallory Alcoholic hyaline
Intracellular ProteinsAlcoholic Hyaline
Pigments
• Exogenous pigments– Carbon (anthracosis)– Tattooing– Natural substances
• b carotiene– Poisons
• lead (pica)
Iron Overload
• Hemosiderosis– Iron overload in phagocytic cells– No tissue damage
• Hemochromatosis– Iron overload in parenchymal cells– Tissue damage
Metastatic Calcification
• Deposition of calcium in normal tissues due to hypercalcemia
• Interstitial tissues of blood vessels, kidneys, lungs, and gastric mucosa
Dystrophic Calcification• Deposition of calcium salts in necrotic
tissues• Intracellular, extracellular, or both• Heterotopic bone may form with time
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