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Questions and Answers
In irreversible cell injury, which of the following nuclear changes indicates the complete dissolution of the nucleus, representing an advanced stage of cellular degradation?
In irreversible cell injury, which of the following nuclear changes indicates the complete dissolution of the nucleus, representing an advanced stage of cellular degradation?
- Karyopyknosis, characterized by the clumping of the nuclear material.
- Karyolysis, distinguished by the fading of the nucleus. (correct)
- Hyperchromasia, identified by an increased staining intensity of the nucleus.
- Karyorrhexis, marked by the fragmentation of the nucleus into smaller pieces.
In the context of cellular response to injury, what critical distinction differentiates reversible cell injury from irreversible cell injury?
In the context of cellular response to injury, what critical distinction differentiates reversible cell injury from irreversible cell injury?
- Reversible injury always progresses to necrosis, while irreversible injury results in apoptosis.
- Reversible injury exclusively involves changes in the cytoplasm, while irreversible injury affects only the nucleus.
- Reversible injury allows the cell to return to its normal state after the stressor is removed, whereas irreversible injury leads to cell death. (correct)
- Reversible injury only occurs in epithelial cells, whereas irreversible injury occurs in connective tissue cells.
During cellular hypoxia, the dysfunction of the sodium-potassium pump leads to an influx of sodium ions into the cell. What is the primary consequence of this ionic imbalance regarding water movement and cellular volume?
During cellular hypoxia, the dysfunction of the sodium-potassium pump leads to an influx of sodium ions into the cell. What is the primary consequence of this ionic imbalance regarding water movement and cellular volume?
- The sodium-potassium pump dysfunction prevents water from leaving the cell, promoting water retention and swelling.
- Efflux of water, leading to cellular shrinkage (atrophy).
- Influx of water, causing cellular swelling (hydropic change). (correct)
- No change in water movement because the increased intracellular sodium is compensated by increased extracellular potassium, maintaining osmotic balance.
In the context of irreversible cell injury, what enzymatic event is most directly responsible for compromising the integrity of cellular membranes, leading to cell lysis and the release of intracellular contents?
In the context of irreversible cell injury, what enzymatic event is most directly responsible for compromising the integrity of cellular membranes, leading to cell lysis and the release of intracellular contents?
Following hypoxic injury to a cell, anaerobic glycolysis is initiated as a compensatory mechanism. What is the MOST significant consequence, contributing to cellular damage during this process?
Following hypoxic injury to a cell, anaerobic glycolysis is initiated as a compensatory mechanism. What is the MOST significant consequence, contributing to cellular damage during this process?
In the context of hypoxic cell injury, what is the direct consequence of cytochrome c release from the mitochondria into the cytosol?
In the context of hypoxic cell injury, what is the direct consequence of cytochrome c release from the mitochondria into the cytosol?
In a liver biopsy of a chronic alcoholic, hepatocytes show significant lipid accumulation (steatosis). What cellular mechanism primarily explains this phenomenon?
In a liver biopsy of a chronic alcoholic, hepatocytes show significant lipid accumulation (steatosis). What cellular mechanism primarily explains this phenomenon?
Following ischemia-reperfusion injury, which of the following mechanisms contributes most significantly to the exacerbation of tissue damage upon restoration of blood flow?
Following ischemia-reperfusion injury, which of the following mechanisms contributes most significantly to the exacerbation of tissue damage upon restoration of blood flow?
What is the primary reason that cells undergoing necrosis release intracellular enzymes into the bloodstream, whereas cells undergoing apoptosis typically do not?
What is the primary reason that cells undergoing necrosis release intracellular enzymes into the bloodstream, whereas cells undergoing apoptosis typically do not?
In the context of cellular injury, what is the role of calcium influx in the progression from reversible to irreversible cell damage?
In the context of cellular injury, what is the role of calcium influx in the progression from reversible to irreversible cell damage?
Flashcards
Reversible Cell Injury
Reversible Cell Injury
Initial cell changes due to stress; cells can recover if the stressor stops.
Irreversible Cell Injury
Irreversible Cell Injury
Cell damage is too severe, and the cell cannot return to a normal state; leads to cell death.
Apoptosis or Necrosis
Apoptosis or Necrosis
Cell death mechanisms, including controlled self-destruction and uncontrolled cell breakdown.
Plasma Membrane Breakdown
Plasma Membrane Breakdown
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Karyopyknosis
Karyopyknosis
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Karyorrhexis
Karyorrhexis
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Karyolysis
Karyolysis
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Fatty Change (Steatosis)
Fatty Change (Steatosis)
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Importance of Oxygen
Importance of Oxygen
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Anaerobic Glycolysis
Anaerobic Glycolysis
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Study Notes
- Cell injury occurs when cells encounter stress or harmful conditions and cannot adapt.
- Reversible cell injury: the initial changes that allow cells to return to normal if the stressor is removed in time.
- Irreversible cell injury: occurs when harm is excessive or persistent, leading to a point of no return.
- Apoptosis and necrosis are both forms of cell death that may result from irreversible cell injury.
Mechanisms of Injury
- Free radicals can damage DNA, but protective factors can counteract them.
- Increased cell permeability leads to an influx of calcium and mitochondrial damage.
Morphologic Features of Reversible Cell Injury
- Dysfunction of the sodium-potassium pump leads to water influx, causing cell swelling.
- Membrane blebbing and organelle swelling can occur.
- Lipid accumulation can be seen in liver hepatocytes.
Irreversible Cell Injury Changes
- Plasma membrane breakdown causes leakage of cellular contents and enzymes.
- Nuclear damage causes loss of DNA and chromatin integrity.
- Necrosis may occur, indicated by nuclear changes like:
- Karyopyknosis: condensation of nuclear chromatin
- Karyorrhexis: fragmentation of the nucleus
- Karyolysis: obliteration of nuclear content
Histologic Light Microscopy
- Normal renal tubules have distinct nuclei surrounded by pink cytoplasm.
- Reversible injury shows cytoplasmic blebbing, swelling, and disrupted architecture.
- Irreversible injury involves loss of nuclei, ghost cells, and coagulative necrosis
Lipid Accumulation (Fatty Change or Steatosis)
- Occurs in hepatocytes, especially with alcohol-induced fatty liver.
- Alcohol disrupts fatty acid oxidation.
- It is potentially reversible if alcohol consumption stops.
Oxygen and Cellular Energy
- Oxygen is required for cells to produce energy in the form of ATP.
- ATP is the molecular unit of currency for cells.
- Mitochondria use oxygen in oxidative phosphorylation to produce ATP.
- Hypoxia: Without oxygen, ATP production halts and can lead to cellular damage.
Hypoxia and Cellular Damage
- Hypoxia prevents ATP production, disrupting cellular processes.
- Sodium-potassium pump dysfunction leads to sodium accumulation inside the cell, causing water influx and cell swelling.
- Reduced cell surface area results from cell swelling.
- The cytoskeleton may fail, leading to membrane blebbing.
- Rough endoplasmic reticulum swelling causes ribosome detachment, halting protein synthesis.
Anaerobic Glycolysis and Acidosis
- Anaerobic glycolysis is a backup ATP production method without oxygen, but is inefficient.
- Only 2 ATP molecules per glucose are produced.
- Lactic acid is a byproduct, lowering intracellular pH and damaging enzymes.
Calcium Influx
- Triggers activation of harmful enzymes:
- Proteases: damage the cytoskeleton
- Endonucleases: damage DNA
- Phospholipases: damage the cell membrane
- Damaged lysosomal membranes begin the process of self-digestion.
Mitochondrial Dysfunction
- Calcium entry into the mitochondria increases membrane permeability.
- Cytochrome c is released into the cytosol, triggering apoptosis.
Apoptosis
- Programmed cell death occurs because of severe damage such as hypoxia.
- The cell undergoes "cellular suicide" when damage reaches an irreversible stage.
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