Introduction to Cellular Injury

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Questions and Answers

What is the primary reason for cellular injury due to oxygen deprivation?

Stable membrane function

Enhanced aerobic metabolism

Increased ATP production

Decreased ATP production (correct)

Which of the following best describes irreversible cellular injury?

Damage that leads to apoptosis (correct)

Transitory respiratory stress

Cellular swelling that is fully reversible

Complete restoration of cellular function

What is a significant consequence of ATP depletion in cells?

Formation of new cellular membranes

Activation of aerobic respiration

Failure of ATP-dependent pumps (correct)

Increase in mitochondrial activity

Which component is primarily damaged by ultraviolet light, according to the content?

DNA Signup and view all the answers

What is the effect of the damaged sodium-potassium membrane pump during cellular swelling?

Net influx of Na+ and Ca2+ ions Signup and view all the answers

What pathological condition results from excessive calcium within cells due to membrane damage?

Induction of apoptosis Signup and view all the answers

Which of the following processes occurs during ATP depletion as cells undergo injury?

Initiation of anaerobic metabolism Signup and view all the answers

Which condition is characterized by reversible cellular swelling?

Cellular hypoxia Signup and view all the answers

What condition is characterized by the appearance of small clear vacuoles in the cytoplasm?

Hydropic change Signup and view all the answers

Which of the following best describes hydropic degeneration?

It occurs with hypo-kalemia due to vomiting or diarrhea. Signup and view all the answers

What is the first stage of cellular necrosis?

Pyknosis Signup and view all the answers

What process is primarily responsible for programmed cell death?

Apoptosis Signup and view all the answers

Which of the following changes is not associated with reversible cell injury?

Irreversible damage to the plasma membrane Signup and view all the answers

Which statement is true regarding fatty change in cells?

It is associated with the inability to metabolize fat. Signup and view all the answers

What role do caspases play in apoptosis?

They cleave specific proteins in the cytoplasm and nucleus. Signup and view all the answers

Which type of cellular damage is characterized by irreversible damages such as organelle breakdown?

Necrosis Signup and view all the answers

Study Notes

Introduction to Cellular Injury

Cellular injury refers to changes in cells due to stress from both external and internal sources.
Cells can adapt to maintain their steady state, however, persistent stress can lead to three outcomes: adaptation, reversible injury, or irreversible injury.

Causes of Cellular Injury

Oxygen Deprivation (Hypoxia)
Physical Agents: Trauma, heat, cold
Chemical Agents: Drugs and other chemicals
Infectious Agents: Bacteria, viruses, parasites
Impaired Nutrient Supply: Lack of essential nutrients
Genetic Derangements: Mutations, genetic disorders
Immunologic Disorders: Autoimmunity, hypersensitivity reactions
Iatrogenic: Caused by medical treatment

Targets of Cell Damage

DNA Damage: Environmental factors and normal metabolic processes can cause DNA damage, leading to millions of molecular lesions per cell each day.
Cell Membrane Damage: Disrupts the balance of electrolytes, particularly calcium, which can trigger apoptosis or programmed cell death.

Biochemical Changes in Cellular Injury

ATP Depletion: A key factor in cellular injury.
- Consequences: Failure of sodium-potassium and calcium pumps, leading to electrolyte imbalances and swelling.
- Glycogenolysis: Anaerobic metabolism occurs to compensate for ATP depletion.
- Decreased pH: Impacts cell function and can promote harmful enzymatic processes.
- Nuclear Changes: Leads to pyknosis (clumping of chromatin) and ultimately can lead to cell death.

Types of Cellular Injury

Sub-lethal (Reversible)
- Cellular Swelling: Caused by hypoxia, which damages the cell membrane's sodium-potassium pump. This can be reversed if the cause is eliminated.
- Hydropic Change or Vacuolar Degeneration: A more severe form of cellular swelling associated with low potassium levels.
- Ultra-structural Changes: Blebbing, blunting, distortion of microvilli, loosening of intercellular attachments, mitochondrial changes, and dilation of the endoplasmic reticulum are all signs of reversible cell injury.
Lethal (Irreversible)
- Necrosis: Characterized by swelling, irreversible membrane damage, and organelle breakdown.
  - Stages:
    - Pyknosis: Nuclear shrinkage and chromatin clumping.
    - Karyorrhexis: Fragmentation of nucleus and chromatin.
    - Karyolysis: Dissolution of the cell nucleus
  - Inflammatory Response: Leakage of cellular components into the extracellular space triggers an inflammatory response.
- Apoptosis: Programmed cell death of excessive or potentially harmful cells.
  - Mechanism: Mediated by caspases, proteolytic enzymes that cleave specific proteins, leading to cell death.
  - Characteristics: Cells shrink and condense into small bodies.
  - Advantages: Cytosolic products are safely contained by membranes, preventing damage to neighboring cells.
  - Consequences: Inhibition of apoptosis can contribute to cancer, autoimmune diseases, inflammatory diseases, and viral infections.

Fatty Change

Occurs when a damaged cell is unable to adequately metabolize fat, resulting in accumulation of fat vacuoles within the cytoplasm.
Liver: Can lead to cholestasis (reduced bile flow) due to fat accumulation compressing bile canaliculi.
Typically reversible.

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Description

This quiz explores the concept of cellular injury, detailing the various causes and effects on cell function. Learn about cellular adaptation, reversible and irreversible injuries. Test your understanding of how different agents affect cell health.