Cell Injury Cell and Tissue Adaptation Necrosis and Apoptosis

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Cell Injury Cell and Tissue AdaptationNecrosis
and Apoptosis

• Dr. Raid Jastania

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Cell Tissue Organ System
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• Intended Learning Outcomes
• Students should list all the causes of cell
  injury.
• Students should understand how the concept of
  cell injury is useful in causation of diseases.
  Students should apply this concept to list the
  possible causes of diseases of any tissue or
  organ in the body.
• Students should understand the consequences of
  cell injury and the targeted structures of the
  cell.
• Students should know the morphologic changes in
  cell death (necrosis and apoptosis)
• Students should understand the meaning of
  apoptosis and the major events in this process.
• 6. Students should know the types of adaptive
  responses and be able to give examples of each
  type.

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What is Cell Injury?What is Cell Death?How
does injury cause death?
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Cell Injury and Cell DeathCharacteristics of
InjuryType, Severity, DurationCharacteristics
of CellType, Status, Genetic makeup, adaptation
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• Causes of Cell Injury
• Infection
• Physical injury
• Chemical injury
• Hypoxia/ ischemia
• Nutritional
• Immunologic
• Genetic
• 8.Aging

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Reversible Injury Irreversible Injury
Functional defect Structural Defect
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• There are 4 main structures that may be targeted
  by injury
• Cell membrane
• Mitochondria (ATP production)
• Protein
• DNA (genetic material)

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• Biochemical mechanisms in cell injury
• ATP depletion
• Mitochondrial damage
• Plasma membrane permeability defect
• Oxygen free radicals
• Ca influx to the cell

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Example of Cell Injury Ischemic and Hypoxic
Injury

• Hypoxia vs. Ischemia
• Stop of ATP-dependent Na-pump. Resulting in
  increase Na and water, and loss of K. The end
  result is cell swelling.
• Anaerobic glycolysis results in production of
  lactic acid and drop of pH
• Later there is swell in of the rough endoplasmic
  reticulum and detachment of the ribosomes and
  reduction in protein synthesis.
• 4. After this stage there is influx of Ca
  and activation of catabolic enzymes with cell
  death.

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Reperfusion Injury

1. Increase Ca supply by blood and increase influx
   of Ca
2. Delivery of inflammatory cells which worsen the
   injury by there action
3. Increase in oxygen free radicals when oxygen is
   delivered to cells

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Application Cell Injury

• Think of tissues or organs with a defect that
  results in cell death (eg. Ulcer of skin or
  mucosa, necrosis of liver, lung, and other
  organs)
• List the causes of cell death in each of these
  tissues and organs.

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Free Radical Induced Cell Injury

• Free radicals are generated in the cell by
• Mitochondrial oxidation superoxide (O2-),
  Hydrogen peroxide (H2O2), Hydroxil group (OH)
• Metabolism of iron and copper
• Nitric oxide
• Radiation UV and x-ray

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Free Radical Induced Cell Injury

• How free radicals cause injury
• Lipid peroxidation
• DNA fragmentation
• Cross-linking of proteins

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Free Radical Induced Cell Injury

• How cells prevent injury by free radicals
• Superoxide dismutase
• Glutathione peroxidase
• Antioxidant (vit E, A, C)
• 4.Transport proteins (transferring)

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• Intended Learning Outcomes
• Students should list all the causes of cell
  injury.
• Students should understand how the concept of
  cell injury is useful in causation of diseases.
  Students should apply this concept to list the
  possible causes of diseases of any tissue or
  organ in the body.
• Students should understand the consequences of
  cell injury and the targeted structures of the
  cell.
• Students should know the morphologic changes in
  cell death (necrosis and apoptosis)
• Students should understand the meaning of
  apoptosis and the major events in this process.
• 6. Students should know the types of adaptive
  responses and be able to give examples of each
  type.