Podcast
Questions and Answers
Which type of cell injury is characterized by severe plasma membrane damage and an inflammatory response?
Which type of cell injury is characterized by severe plasma membrane damage and an inflammatory response?
What type of necrosis is most commonly associated with tuberculosis infections?
What type of necrosis is most commonly associated with tuberculosis infections?
Which factor primarily contributes to irreversible cell injury and death?
Which factor primarily contributes to irreversible cell injury and death?
Which process involves a reversible change in which one adult cell type is replaced by another?
Which process involves a reversible change in which one adult cell type is replaced by another?
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What is the primary cause of atrophy in muscle tissue following a period of inactivity?
What is the primary cause of atrophy in muscle tissue following a period of inactivity?
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In which condition is dystrophic calcification typically observed?
In which condition is dystrophic calcification typically observed?
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Which type of necrosis is characterized by the transformation of tissue into a viscous mass due to bacterial infection?
Which type of necrosis is characterized by the transformation of tissue into a viscous mass due to bacterial infection?
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Which adaptation occurs during normal development and is known as a physiological process?
Which adaptation occurs during normal development and is known as a physiological process?
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What hallmark features are associated with reversible cell injury?
What hallmark features are associated with reversible cell injury?
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Which cellular response occurs when cells can undergo mitosis due to increased demand?
Which cellular response occurs when cells can undergo mitosis due to increased demand?
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Which of the following is NOT considered a cause of cell injury?
Which of the following is NOT considered a cause of cell injury?
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What type of hyperplasia is seen in hormonal stimulation of the normal uterus during pregnancy?
What type of hyperplasia is seen in hormonal stimulation of the normal uterus during pregnancy?
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In which scenario would hypertrophy typically be observed?
In which scenario would hypertrophy typically be observed?
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What is the main difference between physiologic and pathologic hyperplasia?
What is the main difference between physiologic and pathologic hyperplasia?
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Which of the following best describes the type of cellular adaptation when cells increase in size due to specific hormonal stimulation?
Which of the following best describes the type of cellular adaptation when cells increase in size due to specific hormonal stimulation?
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Which of the following agents is NOT a recognized cause of cell injury?
Which of the following agents is NOT a recognized cause of cell injury?
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What characterizes pathologic hyperplasia as opposed to physiologic hyperplasia?
What characterizes pathologic hyperplasia as opposed to physiologic hyperplasia?
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Which of the following statements regarding hypertrophy is correct?
Which of the following statements regarding hypertrophy is correct?
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Study Notes
Causes of Cell Injury
- Trauma
- Physical agents (heat/cold)
- Chemical agents
- Drugs
- Infectious agents (bacterial, viral, fungal, mycobacterial, parasites)
- Immunologic/autoimmune issues
- Genetic factors
- Nutritional deficiencies
- Vascular issues
- Neoplasia (tumors)
- Environmental factors (e.g., silica)
- Metabolic issues (e.g., endocrine)
- Iatrogenic (due to medical treatment)
Cellular Responses to Stress & Stimuli
- Cellular responses are reversible up to a point.
- Cells adapt (change) in structure and function.
Cellular Adaptations: Hyperplasia & Hypertrophy
- Hyperplasia: Increase in cell number
- Hypertrophy: Increase in cell size
- Cells capable of mitosis respond with hyperplasia; cells unable to undergo mitosis (e.g., cardiac muscle) undergo hypertrophy.
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Physiological hyperplasia:
- Hormonal (e.g., uterus during pregnancy)
- Compensatory (e.g., liver regeneration)
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Pathological hyperplasia:
- Excessive hormonal stimulation, abnormal but controlled.
Cellular Adaptations: Atrophy
- Atrophy: Shrinkage of cell size due to loss of cellular substance.
- Physiological atrophy: Normal development
- Pathological atrophy: Local or generalized, dependent on cause
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Causes of atrophy:
- Decreased workload
- Loss of innervation
- Diminished blood supply
- Inadequate nutrition
- Loss of endocrine stimulation
- Aging
- Pressure
Cellular Adaptations: Metaplasia
- Metaplasia: Reversible change where one adult cell type is replaced by another adult cell type.
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Examples:
- Columnar to squamous epithelium (e.g., bronchial epithelium in smokers, or biliary tree epithelium in cases of gallstones)
- Squamous to columnar (e.g., esophageal epithelium in response to acid reflux)
Manifestations of Adaptation or Sub-lethal Cell Injury: Intracellular Accumulations
- Accumulation of substances (metabolites)
- Can be
- Normal (lipids, proteins)
- Abnormal
- Endogenous (e.g., lipid storage diseases)
- Exogenous (e.g., silicosis)
Pathologic Calcification
- Dystrophic calcification: Calcium deposits in previously injured tissue.
- Metastatic calcification: Calcium deposits in originally healthy tissue due to hypercalcemia (e.g., nephrocalcinosis)
Cell Injury
- Occurs when cells are unable to adapt or are exposed to damaging agents.
Reversible Cell Injury
- Reversible injuries can recover if the damaging stimulus is removed.
-
Hallmarks:
- Reduced oxidative phosphorylation
- ATP depletion
- Cellular swelling (changes in ion concentrations & water influx)
Microscopic Changes in Reversible Cell Injury
- Cellular swelling
- Fatty change
Causes of Cell Injury (Recap)
- Hypoxia (ischemia, cardio/respiratory failure, blood loss, anemia, carbon monoxide poisoning)
- Physical agents
- Chemical agents/drugs
- Infectious agents
- Immunologic reactions
- Genetic derangements
- Nutritional imbalances
- Vascular issues
- Neoplasia
- Environmental factors
- Metabolic/endocrine issues
- Iatrogenic (medical treatment related)
Irreversible Cell Injury & Death
-
Hypoxia is a common cause.
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Two types of cell death:
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Necrosis:
- Severe plasma membrane damage
- Internal organelle dysfunction
- Release of cellular contents causing inflammation
- Always pathological
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Apoptosis:
- Cell DNA/protein damage beyond repair
- Cell programmed for destruction
- No inflammatory response.
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Morphologic Changes in Necrosis (Light Microscopy)
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Patterns of necrosis in whole tissues/organs
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Coagulative necrosis:
- Preservation of tissue architecture for a few days
- Structural and enzymatic denaturation
- Eosinophilic, anucleated cells
- Commonly related to ischemia
- Infarction is a localized area of coagulative necrosis.
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Liquefactive necrosis:
- Digestion of cells, formation of liquid mass
- Bacterial/fungal infections
- Ischemic damage to the brain.
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Gangrenous necrosis:
- "Dry" gangrene = coagulative necrosis in an extremity
- "Wet" gangrene = liquefactive necrosis with infection
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Caseous necrosis:
- "Cheese-like" necrosis in tuberculosis
- Granulomas (inflammation foci)
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Fat necrosis:
- Destruction of fat cells
- Often linked to pancreatitis, breast trauma
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Fibrinoid necrosis:
- Immunologic reactions in blood vessels
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Description
This quiz explores the various causes of cell injury, including trauma, chemical agents, and genetic factors. It also covers cellular responses to stress and the adaptations cells undergo, such as hyperplasia and hypertrophy. Prepare to test your knowledge on the mechanisms behind cellular changes.
