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Cell Injury Cell and Tissue Adaptation Necrosis and Apoptosis

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Cell Injury Cell and Tissue Adaptation Necrosis and Apoptosis Powered By Docstoc
					        Cell Injury
Cell and Tissue Adaptation
 Necrosis and Apoptosis

      Dr. Raid Jastania
Cell – Tissue – Organ – System
• Intended Learning Outcomes:
1. Students should list all the causes of cell injury.
2. 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.
3. Students should understand the consequences of cell injury
   and the targeted structures of the cell.
4. Students should know the morphologic changes in cell
   death (necrosis and apoptosis)
5. 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.
   What is Cell Injury?
   What is Cell Death?
How does injury cause death?
Cell Injury and Cell Death

 Characteristics of Injury
         Type, Severity, Duration



  Characteristics of Cell
 Type, Status, Genetic makeup, adaptation
• Causes of Cell Injury:
1.Infection
2.Physical injury
3.Chemical injury
4.Hypoxia/ ischemia
5.Nutritional
6.Immunologic
7.Genetic
8.Aging
Reversible Injury – Irreversible
 Injury – Functional defect –
      Structural Defect
• There are 4 main structures that may be
  targeted by injury:
1.Cell membrane
2.Mitochondria (ATP production)
3.Protein
4.DNA (genetic material)
• Biochemical mechanisms in cell injury:
1.ATP depletion
2.Mitochondrial damage
3.Plasma membrane permeability defect
4.Oxygen free radicals
5.Ca++ influx to the cell
    Example of Cell Injury:
 Ischemic and Hypoxic Injury:
• Hypoxia vs. Ischemia
1. Stop of ATP-dependent Na-pump. Resulting in
   increase Na+ and water, and loss of K+. The
   end result is cell swelling.
2. Anaerobic glycolysis results in production of
   lactic acid and drop of pH
3. 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.
         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
    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.
 Free Radical Induced Cell Injury:

• Free radicals are generated in the cell by:
1.Mitochondrial oxidation: superoxide (O2-),
  Hydrogen peroxide (H2O2), Hydroxil group
  (OH)
2.Metabolism of iron and copper
3.Nitric oxide
4.Radiation UV and x-ray
 Free Radical Induced Cell Injury:

• How free radicals cause injury:
1.Lipid peroxidation
2.DNA fragmentation
3.Cross-linking of proteins
 Free Radical Induced Cell Injury:

• How cells prevent injury by free radicals:
1.Superoxide dismutase
2.Glutathione peroxidase
3.Antioxidant (vit E, A, C)
4.Transport proteins (transferring)
• Intended Learning Outcomes:
1. Students should list all the causes of cell injury.
2. 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.
3. Students should understand the consequences of cell injury
   and the targeted structures of the cell.
4. Students should know the morphologic changes in cell
   death (necrosis and apoptosis)
5. 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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posted:10/9/2012
language:English
pages:16