Cell Response to Injury Quiz

Cell Response to Injury

• A sequence of biochemical and morphologic events occurs when a cell is exposed to an injurious agent.
• The effects of cell injury depend on the severity and duration of the injurious agent, and the cell's vulnerability.
• Possible outcomes include adaptation, reversible injury, and irreversible injury (leading to cell death).

Causes of Cell Injury

• Hypoxia: Oxygen deficiency; often due to ischemia (impaired blood supply), inadequate oxygenation of blood, or loss of oxygen-carrying capacity (anemia).
• Physical Agents: Trauma, radiation, extreme temperatures, electric shock.
• Chemicals and Drugs: Acids, alkalies, animal and plant poisons.
• Microbiologic Agents: Viruses, worms, bacteria.
• Immunologic Reactions: Allergic reactions, autoimmune diseases.

Types of Cell Injury: Reversible

• Cloudy Swelling: Accumulation of water within cells, leading to swelling. This is an early, reversible form of injury.
• Hydropic Swelling: A more severe form of water accumulation, characterized by vacuoles within the cytoplasm.
• Fatty Change: Abnormal accumulation of fat within parenchymal cells; often affects the liver, but can also affect the heart, kidneys, and muscles.

Types of Cell Injury: Irreversible

• Necrosis: A form of cell death marked by cell lysis and inflammation.
• Apoptosis: Programmed cell death that is generally not accompanied by inflammation.

Effects of Cell Injury

• The severity and duration of the injurious agent and the cell's vulnerability determine the outcome.
• Initial response may be adaptation; if the stimulus persists, the cell may suffer reversible injury; ultimately, irreversible injury and cell death result.

Cellular Adaptations

• Hyperplasia: Increased number of cells.
• Hypertrophy: Increased size of cells.
• Metaplasia: Conversion of one cell type to another.

Morphology of Injury (Clinical Pictures)

• Kidney: Proteinuria (protein in urine) often accompanies cloudy swelling.
• Liver: No significant changes are seen in early stages of cloudy swelling.
• Heart: Often enlarged and shows dilation.

Clinical Picture Summary

• Kidney (reversible injury): Possible proteinuria (protein in the urine).
• Liver (reversible injury): Typically shows no significant changes in early stages.
• Heart (reversible injury): Often shows dilation.

Quiz Questions (Examples)

• Degeneration means reversible cell injury.
• Liver cells with fat accumulation typically show a signet-ring appearance.