Term
| Describe reversible (non-lethal) cell injury |
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Definition
Cells swell following acute, non-lethal injury due to an increase in intracellular water (hydropic swelling). This condition is fully reversible.
Cellular changes in reversible cell injury are hydropic (cloudy) swelling, distention of endoplasmic reticulum, mitochondrial swelling, plasma membrane blebs, and nucleolar fibrillar/granular changes
These cellular and ultrastructural changes are in large part mediated by a decrease in intracellular ATP levels and/or impairment of the membrane Na/K ATPase |
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Term
| What are the possible causes of hydropic swelling? |
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Definition
| Insufficient ATP to drive Na+ pumps, leaky plasma membrane, or Na+/K+ ATPase is failing |
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Term
| What is the difference between ischemia and partial ischemia? |
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Definition
Ischemia is interference with blood supply to tissues. Total ischemia results in cell death
Partial ischemia is a situation where there is chronically reduced oxygen supply, compatible with cell viability. However, under such circumstances cell atrophy is common. |
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Term
| What is the most common form of metaplasia? |
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Definition
Squamous metaplasia
The most common sequence is replacement of glandular epithelium by a squamous one. It is almost invariably a response to persistent injury and can be thought of as an adaptive mechanism. |
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Term
| Prolonged exposure of the bronchi to tobacco smoke leads to what type of metaplasia? |
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Definition
Squamous metaplasia of the bronchial epithelium
Metaplasma is usually reversible if the stimulus is removed |
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Term
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Definition
Alteration in size, shape, and organization of the cellular components of a tissue
It occurs most commonly in hyperplastic squamous epithelium (skin, cervix, and bronchus) and reflects persistent injury to the tissue
Dysplasia shares many cytologic features with in situ cancer and it may be a problem to the pathologist. It is established that dysplasia is a pre-neoplastic lesion. |
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Term
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Definition
Storage form of iron in cell. Stains blue when using Prussian Blue.
Present in slides from patients with Hereditary Hemochromatosis. |
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Term
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Definition
A "wear and tear" pigment of aging that is composed of golden-brown lipoprotein granules. It is found predominantly in cells that are terminally differentiated (cadiac myocytes) or that cycle only infrequently (hepatocytes).
Stains yellow on H&E. |
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Term
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Definition
Coal-miner lung
Due to storage of carbon particles in the lung and regional lymph nodes. |
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Term
| What are the cellular changes in irreversible cell injury? |
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Definition
| Plasma membrane blebs, increased intracellular volume, swelling and calcification of mitochondria, aggregation of cytoskeletal elements, disaggregation of ribosomes, dilation of ER cisternae, chromatin condensation (pyknosis), and progressive fragmentation of chromatin (karyorrhexis and karyolysis) |
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Term
| What are the morphological patterns of coagulative necrosis? |
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Definition
| Includes changes in both the cytoplasm and nucleus. When stained by hematoxylin and eosin, the cytoplasm is more eosinophilic. The nucleus becomes smaller and deeply basophilic as a result of chromatin clumping. |
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Term
| What is liquefactive necrosis? |
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Definition
| It occurs when the rate of tissue dissolution is faster than the rate of healing and repair. This phenomenon is commonly observed in acute inflammatory reactions (bacterial infections) and following coagulative necrosis in the brain. |
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Term
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Definition
Specifically affects adipose tissue and results from pancreatitis or trauma. It is due to the liberation of lipases. Affects peripancreatic tissue due to binge drinking.
Produces a chalky substance with is the same reaction used to make soap. |
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Term
| What is caseous necrosis? |
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Definition
Characteristic of TB. In the center of the tuberculous granulomas, dead cells persist as amorphous, coarsely granular, eosinophilic debris.
Produces "cheese-like" lesions |
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Term
| Describe fibrinoid necrosis |
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Definition
| Refers to alterations in the walls of blood vessels, in which the insudation and accumulation of plasma proteins causes the walls to stain with eosin. |
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Term
| What is the pathogenesis of coagulative necrosis? |
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Definition
Irreversible injury and cell death
Loss of plasma membrane integrity
Influx of sodium, calcium, and water
Appearance of coagulative necrosis |
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Term
| What are the possible mechanisms of membrane damage in irreversible cell injury? |
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Definition
Enzymatic degradation of membrane phospholipids
Disruption of membrane-cytoskeleton contacts
Peroxidation and degradation of phospholipids
Cross-linking of membrane proteins |
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Term
| What is the most important cause of coagulative necrosis in humans? |
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Definition
| Interruption of blood flow - ischemia |
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Term
| Describe ischemic cell damage |
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Definition
With short periods of ischemia, reperfusion completely restores the structural and functional integrity of the cell.
With longer periods of ischemia, reperfusion is not associated with restoration of cell structure, but rather with deterioration and death of the cells owing to the formation of reactive oxygen species |
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Term
| What does ionizing radiation do and is it bad? |
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Definition
| Ionizing radiation causes radiolysis of water, resulting in the formation of hydroxyl radicals. Hydroxyl radicals can cross link proteins, inhibit replication and initiate lipid peroxidation, with consequent damage to the cell membrane. So yeah, ionizing radiation is bad. |
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Term
| What is the difference between directly cytopathic and indirectly cytopathic viruses? |
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Definition
Directly cytoplathis viruses kills cells in a manner that does not require participation of the immune system. Viral proteins are inserted into the plasma membrane, forming a pore that disrupts the permeability barrier of the host cell, causing ionic equilibrium with the external environment and cell death.
Indirectly cytopathic viruses kill cells via activation of the immune system. |
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Term
| Describe the action of a directly cytopathic virus |
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Definition
| Viral proteins are inserted into the plasma membrane, forming a pore that disrupts the permeability barrier of the host cell, causing ionic equilibrium with the external environment and cell death. |
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Term
| Describe the actions of an indirectly cytopathic virus |
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Definition
| Viral proteins are exposed on the surface of infected cells and are recognized by T lymphocytes as viral antigens, releasing a perforin protein that interacts with the host plasma membrane causing a disruption in its integrity and eventual cytolysis. In addition, T lymphocytes may release a protein (granzyme) that activates apoptosis. |
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Term
| What are the key regulators of apoptosis? What are the most common initiators? |
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Definition
p53 and caspase cascade
viral infeciton-lymphocyte binding and by DNA damage |
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Term
| Does apoptosis activate the inflammatory system? |
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Definition
| Generally no, as there is usually minimal debris |
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Term
| What is the appearance of apoptotic cells? |
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Definition
| Eosinophilic bodies with dense, often fragmented chromatin, or cells lacking any nuclear material |
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Term
| Apoptosis is often characterized by what? |
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Definition
| Receptor-mediated activation of intracellular proteases (caspases) and by stimulation of endogenous endonuclease activity that leads to cleaveage of nuclear chromatin |
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Term
| What is dystrophic calcification? |
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Definition
| Macroscopic deposition of calcium salts in injured tissues. It represents an extracellular deposition of calcium from the circulation or interstitial fluid. Examples include calcific aortic stenosis. |
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Term
| What is metastatic calcification? |
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Definition
| It reflects damaged calcium metabolism resulting in increased serum calcium concentration (hypercalcemia), as seen in diseases like chronic renal failure and hyperparathyroidism. The formation of stones containing calcium carbonate in sites such as the gallbladder, renal pelvis, etc. is another form of pathological calcification. |
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Term
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Definition
| Inherited syndromes associated with premature aging |
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Term
| What is Hutchinson-Guilford syndrome? |
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Definition
| Severe form of progeria characterized by a mutation in the LMNA gene that codes for a protein called lamin A. The abnormal protein, termed progerin, accumulates within cell nuclei and disrupts nuclear structure and function. |
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Term
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Definition
| A milder form of progeria that results from a mutation in a gene on chromosome 8 that codes for the Werner gene, a DNA helicase, which unwinds the double-stranded DNA. Dysfunction of the mutated helicase leads to a variety of chromosomal abnormalities, which in turn are thought to cause the accelerated aging seen in these patients. Clinical manifestations include premature atherosclerosis, hair loss, cataracts, osteoporosis, development of a variety of cancers, and a shortened lifespan. |
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Term
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Definition
| The study of structural and functional abnormalities that are expressed as diseases of organs and systems |
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Term
| What is hydropic swelling? |
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Definition
| The condition of reversible cell injury characterized by a large, pale cytoplasm and a normally located nucleus. |
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Term
| What are the common causes of cell death? |
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Definition
| Viruses, ischemia, and exposure to physical agents such as ionizing radiation, extreme temperatures, or toxic chemicals. |
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Term
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Definition
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Term
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Definition
| Progressive loss of chromatin |
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