Questions and Answers
Which process primarily involves the action of enzymes on cells following injury?
What is a characteristic feature of cells undergoing apoptosis?
What initiates the extrinsic pathway of apoptosis?
Which of the following is NOT a known cause of apoptosis?
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What morphologic change is associated with necrosis?
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Which of the following is NOT a category of injurious stimuli that can cause cell injury?
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Which mechanism of cell injury is primarily associated with damage to energy production?
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What is the key characteristic of apoptosis?
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Which of the following is an example of irreversible cell injury?
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Which factor is NOT mentioned as one of the most important targets of injurious stimuli?
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What happens during necrosis?
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Which cause of cell injury is a result of a single gene defect?
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Which of the following correctly describes reversible cell injury?
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What is one purpose of apoptosis in physiologic situations?
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Which mechanism is primarily responsible for executing apoptosis?
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In which situation does apoptosis occur to maintain tissue function?
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What triggers apoptosis in pathologic conditions related to DNA damage?
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What role does apoptosis play in the elimination of self-reactive lymphocytes?
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Which of the following is a common pathologic condition that can stimulate apoptosis?
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What is a consequence of apoptosis during embryogenesis?
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How does apoptosis respond to accumulated misfolded proteins?
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What is the primary characteristic that differentiates necrosis from apoptosis in terms of cell size?
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Which of the following forms of necrosis maintains the underlying tissue architecture for several days?
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What happens to the plasma membrane during necrosis compared to apoptosis?
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Which type of necrosis is primarily associated with bacterial or fungal infections?
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What is a common physiological role of apoptosis?
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Which type of necrosis is characterized by a firm texture in the affected tissues?
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In necrosis, what typically happens to the cellular contents?
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Which form of necrosis is typically the end result of irreversible cell injury?
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What is the appearance of caseous necrosis on microscopic examination?
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Which type of necrosis is typically associated with acute pancreatitis?
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What triggers the formation of fibrinoid necrosis?
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What distinguishes gangrenous necrosis from other types of necrosis?
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What is the consequence of fat saponification in fat necrosis?
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Which statement describes autophagy?
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Which of the following is a common feature of caseous necrosis?
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What is NOT typical of fibrinoid necrosis?
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Study Notes
Overview of Cell Injury and Cell Death
- Cell injury can be classified into reversible and irreversible types.
- Stages involved in the progression of cell injury and death are crucial for understanding cellular responses to damage.
Causes of Cell Injury
- Causes range from physical trauma to genetic defects leading to metabolic diseases.
- Major categories of injurious stimuli include:
- Oxygen deprivation
- Physical agents (e.g., trauma, temperature extremes)
- Chemical agents and drugs (toxic substances)
- Infectious agents (bacteria, viruses)
- Immunologic reactions (autoimmune diseases)
- Genetic derangements (mutations)
- Nutritional imbalances (deficiencies or excesses)
- Aging processes
Mechanisms of Cell Injury
- Key mechanisms contributing to cell injury:
- ATP depletion affecting energy production
- Mitochondrial damage impacting cell respiration
- Calcium influx disrupting cellular function
- Increased reactive oxygen species leading to oxidative stress
- Membrane permeability changes compromising cell integrity
- Accumulation of damaged DNA and misfolded proteins
- Important targets of injury include aerobic respiration, cell membrane integrity, protein synthesis, cytoskeleton, and genetic material.
Types of Cell Death
- Two primary forms of cell death:
- Apoptosis: programmed cell death involving self-degradation of nuclear DNA and proteins.
- Necrosis: unregulated cell death due to irreversible injury, typically involving tissue decay and inflammation.
Apoptosis
- Physiologic roles include:
- Programmed cell death during embryogenesis.
- Cell elimination following hormonal changes (e.g., menstrual cycle).
- Maintenance of cell population by removing excess cells in proliferating tissues.
- Removal of self-reactive lymphocytes to prevent autoimmune responses.
- Pathologic conditions leading to apoptosis include:
- DNA damage from radiation or toxins.
- Accumulation of misfolded proteins due to genetic mutations or free radical damage.
Mechanisms of Apoptosis
- Activation of caspases (proteolytic enzymes) drives the process.
- Two pathways:
- Mitochondrial (intrinsic) pathway influenced by mitochondrial permeability.
- Death receptor (extrinsic) pathway triggered by surface molecules on cells.
Morphological Features of Apoptosis
- Cell shrinkage, chromatin condensation, bleb formation, and phagocytosis of apoptotic bodies characterize apoptosis.
Necrosis
- A term describing the morphologic changes after cell death in living tissue due to irreversible injury.
- Features include:
- Pyknosis: nuclear shrinkage and increased basophilia.
- Karyorrhexis: fragmentation of nuclear material.
- Karyolysis: fading basophilia of chromatin.
Differences Between Apoptosis and Necrosis
- Cell Size: Necrosis causes enlarged, swollen cells; apoptosis leads to reduced, shrunken cells.
- Nucleus: In necrosis, nuclear degradation progresses through pyknotic to karyolytic stages; apoptosis results in fragmentation into small pieces.
- Plasma Membrane: Lost integrity in necrosis; remains intact in apoptosis but altered.
- Inflammation: Often present in necrosis, absent or minimal in apoptosis.
- Physiologic Role: Necrosis is pathologic; apoptosis can be physiologic or pathologic.
Patterns of Necrosis
- Different forms include:
- Coagulative: tissue architecture preserved; firm texture after death.
- Liquefactive: occurs in bacterial infections; tissues become liquid due to enzyme action.
- Caseous: usually seen in tuberculosis; necrotic tissue appears cheeselike.
- Fat necrosis: fat tissue destruction due to lipase action, often linked to pancreatitis.
- Fibrinoid: occurs during immune reactions; bright pink appearance due to immune complex deposition.
- Gangrenous: reflects tissue death due to loss of blood supply, may lead to coagulative or liquefactive necrosis.
Additional Concept: Autophagy
- A lysosomal process where cells digest their own components, serving as a survival mechanism under stress conditions.
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Description
Test your understanding of cell injury and cell death concepts in General Pathology for the 1st semester of the 2024-2025 academic year. This quiz covers reversible and irreversible cell injuries, along with stages in the evolution of cell injury. Perfect for students in Medical Laboratory Technology.
