Module 3

• What is necrosis?

  Death of a cell or group of cells
• What causes necrosis?

  Loss of blood supply, toxins, or agents
• What are the types of necrosis?

  • Coagulative necrosis
  • Liquefactive necrosis
  • Caseous necrosis
  • Fat necrosis
  • Gangrenous necrosis
• What characterizes coagulative necrosis?

  Preservation of tissue architecture after cell death
• What happens to cells during coagulative necrosis?

  Cells become denatured and insoluble
• What is Zenker's necrosis?

  Coagulation of proteins in striated muscle
• What is the appearance of necrotic tissue in coagulative necrosis?

  Grey to white, firm, and dense
• What causes liquefactive necrosis?

  Rapid disintegration into a liquid mass
• Where does liquefactive necrosis commonly occur?

  In abscesses and the central nervous system
• What is caseous necrosis?

  A combination of coagulative and liquefactive necrosis
• What diseases are associated with caseous necrosis?

  Tuberculosis and mycotic infections
• What is fat necrosis?

  A type of necrosis involving adipose tissue
• What causes enzymatic fat necrosis?

  Pancreatic damage and activated enzymes
• What is gangrenous necrosis?

  Necrosis invaded by saprophytic bacteria
• What distinguishes dry gangrene from wet gangrene?

  Dry gangrene is cool and shriveled
• What is dystrophic calcification?

  Calcium salts deposited in dead tissues
• What is metastatic calcification?

  Calcium salts deposited in living tissues
• What are cholesterol clefts?

  Empty spaces left by dissolved cholesterol
• What happens to intracellular enzymes in dead cells?

  They leak into the bloodstream
• What is the outcome of necrotic tissue?

  It incites an inflammatory reaction
• What are the ways necrotic tissue can be handled by the body?

  1. Liquefaction with cyst formation
  2. Liquefaction with abscess formation
  3. Encapsulation without liquefaction
  4. Desquamation or sloughing of necrotic tissue
  5. Regeneration or replacement by connective tissue
• What is the significance of elevated intracellular enzymes in blood?

  Indicates presence of dead or damaged cells
• What is the role of leukocytes in necrotic tissue?

  They assist in liquefaction and removal
• How does necrosis affect overall health?

  Can lead to clinical signs of illness
• What do postmortem changes refer to?

  Cell death accompanying the death of the body
• What is the difference between postmortem and antemortem changes?

  Postmortem changes occur after death, antemortem before
• What is somatic death?

  Death of the entire body
• How is somatic death defined?

  By absence of heartbeat, pulse, respiration
• Why is determining the moment of somatic death difficult?

  It has medical, ethical, and legal implications
• How does somatic death differ from cellular death?

  Somatic death is whole body, cellular is individual cells
• What happens to cells after somatic death?

  Cells become ischemic and survive for varying periods
• Why can organs be removed for transplantation after somatic death?

  Cells may survive for hours post-death
• What is postmortem autolysis?

  Self-digestion by enzymes after death
• How does postmortem autolysis differ from necrosis?

  Autolysis occurs after death, necrosis in living cells
• What causes postmortem autolysis?

  Total diffuse anoxia after death
• What factors influence the rate of postmortem autolysis?

  Proteolytic enzyme concentration, temperature, animal condition
• What are the specific types of postmortem changes?

  1. Postmortem putrefaction
  2. Rigor mortis
  3. Algor mortis
  4. Hypostatic congestion
  5. Imbibition with hemoglobin
  6. Imbibition with bile
  7. Pseudomelanosis
  8. Postmortem emphysema
  9. Postmortem rupture
  10. Postmortem displacement of organs
  11. Postmortem clotting of blood
  12. The heart after somatic death
• What is postmortem putrefaction?

  Decomposition of tissues by bacterial enzymes
• What happens to tissues during postmortem putrefaction?

  Tissues become soft and foul-smelling
• What is rigor mortis?

  Stiffening of all muscles after death