Flashcards in Cellular Injury and Adaptation Deck (174)
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Homeostasis
balance of physiologic and biochemical functions within the body
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Alteration of homeostasis results in
stress to cell, cellular injury or adaptive changes to survive altered environment
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Reversible injury
injury is corrected prior to destruction of cellular repair mechanisms; severity of injury does not exceed the cells ability to repair itself
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Irreversible injury
repair mechanisms are destroyed (removal from altered environment will be insufficient) cell cannot repair itself --> DEATH; injury exceeds the cell's ability for self-repair, resulting in cell death
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Cellular Injury
Hypoxia, Physical agents, chemicals, infectious agents, immune reactions, genetic derangements, nutritional imbalance
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Hypoxia
Decreased supply of O2 to cell or inability to use O2
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Anoxia
Complete absence of O2
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Causes of Hypoxia
Ischemia (decreased BF), decreased oxygenation of blood, decreased O2 carrying capacity, inability to utilize O2
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Examples of Physical injury to cell
mechanical trauma, temperature extremes, atmospheric pressure variation, radiation, electrical injury
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Examples of Chemical Injury to cell
Simple agents (electrolytes, glucose), Poisons, Pollutants, Insecticides, herbicides, industrial products, drugs (therapeutic or recreational), alcohol
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Infectious Causes of cell injury
bacteria, rickettsia, fungi, virus, parasite
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Immune Response Causes of cell injury
Hypersensitivity reaction
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4 Key Signs of REVERSIBLE cell injury
Decreased aerobic respiration, cellular edema, ribosome detachment from RER, ultrastructural morphological changes
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Reversible Injury - Decreased Aerobic Respiration Results in
Decreased ATP production, increased AMP and anaerobic glycolysis, Increased lactate (decreased pH), decreased cellular glycogen, clumping of nuclear chromatin, decreased protein synthesis
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Examples of nutritional variations that cause cellular injury
deficits, excess, malabsorption, altered use
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Sites that are altered in cellular injury
cell membrane integrity, aerobic respiration, enzyme/protein synthesis, genetic apparatus
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What causes cellular edema in reversible cell injury?
Suppression of Na+ pump with increased [Na+] retention; increased intracellular Na+
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Ultrastructural Morphological Changes in reversible cellular injury
Phospholipid membrane alteration, loss of microvilli, myelin figure formation, mitochondrial swelling, RER swelling
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Key Signs of IRREVERSIBLE cellular injury
ATP Depletion, Cell Membrane Damage
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Cell Membrane Damage as a result of irreversible damage
Phospholipid Depletion, Cytoskeletal breakdown, toxic ROS, Lipid breakdown products, amino acid loss
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Structural changes in IRREVERSIBLE cell injury include
vacuolization of mitochondria, PM damage, Lysosomal swelling, Loss of proteins, enzymes, and RNA
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What characterizes cell injure as irreversible?
ATP depletion, cellular edema -> PM tears and damage, mitochondrial dysfunction (high [Ca2+] intracellularly), Membrane phospholipid depletion, cytoskeleton changes, ROS, lipid breakdown products, and amino acid loss
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Irreversible Cellular Damage - What is the determining/most important factor?
Cellular Membrane Dysfunction
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Irreversible Cellular Damage - What results from mitochondrial dysfunction?
ATP depletion -> increased cytosolic [Ca2+] -> mitochondrial phospholipase activation -> phospholipid breakdown + accumulation of FFA -> altered permeability of PM
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Myelin figures are characteristic of
reversible injury
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cellular edema is characteristic of
reversible injury
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Irreversible Cellular Damage - What causes membrane phospholipid depletion?
increase [Ca2+] intracellular activation of phospholipase AND ATP-dependent maintenance and production of phospholipids
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Irreversible Cellular Damage - What causes cytoskeletal abnormalities?
Hypoxia AND activation of proteases by high intracellular levels of [Ca2+]
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Irreversible Cellular Damage - What causes Toxic oxygen radical production?
sudden repercussion of hypoxic tissue
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