Cell Injury and Adaptation Overview
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Questions and Answers

Which type of cell injury is characterized by severe plasma membrane damage and an inflammatory response?

  • Atrophy
  • Metaplasia
  • Apoptosis
  • Necrosis (correct)

What type of necrosis is most commonly associated with tuberculosis infections?

  • Coagulative necrosis
  • Fibrinoid necrosis
  • Caseous necrosis (correct)
  • Liquefactive necrosis

Which factor primarily contributes to irreversible cell injury and death?

  • Genetic derangements
  • Nutritional imbalances
  • Physical agents
  • Hypoxia (correct)

Which process involves a reversible change in which one adult cell type is replaced by another?

<p>Metaplasia (D)</p> Signup and view all the answers

What is the primary cause of atrophy in muscle tissue following a period of inactivity?

<p>Decreased workload (C)</p> Signup and view all the answers

In which condition is dystrophic calcification typically observed?

<p>Previously injured tissue (D)</p> Signup and view all the answers

Which type of necrosis is characterized by the transformation of tissue into a viscous mass due to bacterial infection?

<p>Liquefactive necrosis (C)</p> Signup and view all the answers

Which adaptation occurs during normal development and is known as a physiological process?

<p>Atrophy (D)</p> Signup and view all the answers

What hallmark features are associated with reversible cell injury?

<p>Cellular swelling and ATP depletion (D)</p> Signup and view all the answers

Which cellular response occurs when cells can undergo mitosis due to increased demand?

<p>Hyperplasia (A)</p> Signup and view all the answers

Which of the following is NOT considered a cause of cell injury?

<p>Psychological stress (A)</p> Signup and view all the answers

What type of hyperplasia is seen in hormonal stimulation of the normal uterus during pregnancy?

<p>Physiologic hormonal hyperplasia (D)</p> Signup and view all the answers

In which scenario would hypertrophy typically be observed?

<p>Enlargement of cardiac muscle cells due to high blood pressure (D)</p> Signup and view all the answers

What is the main difference between physiologic and pathologic hyperplasia?

<p>Physiologic hyperplasia results from hormonal stimulation while pathologic hyperplasia can result from excessive stimulation. (B)</p> Signup and view all the answers

Which of the following best describes the type of cellular adaptation when cells increase in size due to specific hormonal stimulation?

<p>Physiologic hypertrophy (D)</p> Signup and view all the answers

Which of the following agents is NOT a recognized cause of cell injury?

<p>Excessive exercise (C)</p> Signup and view all the answers

What characterizes pathologic hyperplasia as opposed to physiologic hyperplasia?

<p>It results from excessive or unregulated hormonal stimulation. (D)</p> Signup and view all the answers

Which of the following statements regarding hypertrophy is correct?

<p>Hypertrophy can occur due to increased functional demand. (C)</p> Signup and view all the answers

Flashcards

Cell Injury Causes

Factors that damage cells, including trauma, physical agents, chemicals, drugs, infections, immune responses, genetics, nutrition, vascular problems, neoplasia, and environmental/metabolic factors.

Reversible Cell Injury

A cell's response to stress, initially, can be reversed and the cell can recover functionally and structurally.

Hyperplasia

Increase in the number of cells in response to increased demand.

Hypertrophy

Increase in the size of individual cells in response to increased demand.

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Physiological Hyperplasia

Normal increase in cell number due to hormonal or compensatory factors.

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Pathological Hyperplasia

Abnormal increase in cell number triggered by excessive hormonal stimulation.

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Physiological Hypertrophy

Normal increase in cell size due to increased work demand or hormonal stimulation.

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Pathological Hypertrophy

Abnormal increase in cell size due to increased work demands or abnormal stimulation.

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Mitosis

Cell division process.

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Cell adaptation

A cell's response to stress to maintain homeostasis.

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Cellular Atrophy

Shrinkage of cells due to loss of cell substance.

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Causes of Atrophy

Decreased workload, loss of innervation, poor blood supply or nutrition.

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Cellular Metaplasia

One adult cell type replacing another adult cell type.

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Metaplasia Example

Healthy bronchus lining reverting to squamous cells caused by smoking, or esophagus lining reverting to glandular cells due to stomach acid.

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Intracellular Accumulations

Substances (normal or abnormal) building up inside cells.

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Two Signs of Reversible Injury

Reduced energy production and cell swelling occur.

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Cell Necrosis

Severe cell death with plasma membrane damage and eventual rupture.

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Cell Apoptosis

Programmed cell death without inflammation.

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Coagulative Necrosis

Cell death preserving tissue structure temporarily.

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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.
  • Physiological hyperplasia:
    • Hormonal (e.g., uterus during pregnancy)
    • Compensatory (e.g., liver regeneration)
  • 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
  • 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.
  • 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.

  • Two types of cell death:

    • Necrosis:

      • Severe plasma membrane damage
      • Internal organelle dysfunction
      • Release of cellular contents causing inflammation
      • Always pathological
    • Apoptosis:

      • Cell DNA/protein damage beyond repair
      • Cell programmed for destruction
      • No inflammatory response.

Morphologic Changes in Necrosis (Light Microscopy)

  • Patterns of necrosis in whole tissues/organs

  • 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.
  • Liquefactive necrosis:

    • Digestion of cells, formation of liquid mass
    • Bacterial/fungal infections
    • Ischemic damage to the brain.
  • Gangrenous necrosis:

    • "Dry" gangrene = coagulative necrosis in an extremity
    • "Wet" gangrene = liquefactive necrosis with infection
  • Caseous necrosis:

    • "Cheese-like" necrosis in tuberculosis
    • Granulomas (inflammation foci)
  • Fat necrosis:

    • Destruction of fat cells
    • Often linked to pancreatitis, breast trauma
  • 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.

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