Module 2

• What is the common denominator in almost all diseases?

  Cellular injury
• How is injury defined in the context of cellular injury?

  As an alteration in cell structure or function
• What causes cellular injury according to the definition provided?

  Stress that exceeds the cell's compensatory ability
• What are normal physiologic adaptive mechanisms?

  Processes that help cells compensate for stress
• What does cell injury equate to in medical terms?

  Disease
• What term describes the intensity of a dose in relation to cell injury?

  Dose Intensity
• What does cell stress refer to in the context of cell injury?

  Conditions that challenge cell function
• What is adaptation in relation to cells?

  Cells adjusting to stress or injury
• What are the two main types of changes cells undergo during injury?

  Metabolic and Structural
• What does cell vulnerability indicate?

  Cells' susceptibility to injury
• What does reversible injury mean?

  Injury that can be repaired
• What is referred to as the "point of no return" in cell injury?

  The stage beyond which recovery is impossible
• What does irreversible injury lead to?

  Cell Death
• What are the key concepts related to cell injury?

  • Cell Injury = Disease
  • Dose Intensity
  • Cell Stress
  • Adaptation
  • Metabolic Changes
  • Structural Changes
  • Cell Vulnerability
  • Reversible Injury
  • "Point of no return"
  • Irreversible Injury
  • Cell Death
• What are the two ways cells respond to potentially injurious stress?

  Adaptation and injury
• What is cell adaptation?

  • Alteration of structure/biochemical processes
  • Achieves a new "steady state"
  • Maintains near-normal physiologic functions (homeostasis)
• How do melanocytes adapt to chronic sunlight exposure?

  They synthesize more melanin for protection
• What happens to cells when they are injured?

  • Critical cell functions may be impaired
  • Cells may suffer from irreversible injury
  • Can lead to cell death
• What does it mean if an injury is reversible?

  Injured cells recover normal functions
• What is the "point of no return" in cell injury?

  Severe injury leads to irreversible damage
• What are the two patterns of cell death?

  • Necrosis
  • Apoptosis
• What factors influence how a cell responds to stress?

  The severity/duration of exposure and cell vulnerability
• What happens if the coronary blood supply is interrupted for 1-2 minutes?

  No long-term effects on the myocardium
• What can prolonged cessation of blood flow lead to?

  Death of functional heart tissue
• Which cells can tolerate several hours of interrupted blood flow?

  Hepatocytes and skeletal muscle cells
• Which cells are more sensitive to stress?

  Neurons and myocardium
• How does cell specialization relate to vulnerability to injury?

  The more specialized a cell is, the more vulnerable it is
• What is associated with cell injury?

  Damage to structural and functional molecules
• Which four biochemical systems are particularly vulnerable to cell injury?

  Cell membrane, energy metabolism, protein synthesis, genes
• How does injury at one site affect other cellular processes?

  It typically causes secondary injury to others
• What is the role of selectively permeable lipid membranes?

  Maintain internal environment of cells
• How do plasma membranes help conserve resources?

  By controlling molecule entry and exit
• Why is resting membrane potential important?

  It is crucial for nerve and muscle function
• What happens when the plasma membrane is damaged?

  Increased permeability to sodium and water
• What is the consequence of potassium leaking out of the cell?

  Affects the ability to maintain resting potential
• What does injury to mitochondria impair?

  Energy metabolism
• What does lysosomal injury release into the cytoplasm?

  Hydrolytic enzymes
• What does damage to the endoplasmic reticulum interfere with?

  Protein synthesis and transport
• What do cells use to keep intracellular calcium low?

  Energy-dependent membrane pumps
• What happens when cell membranes are injured regarding calcium ions?

  Calcium ions move into the cytoplasm