Cellular Injury

  1. Cellular adaptation
    A decrease or shrinkage in size
    • Atrophy
    • Can effect skeletal muschle, heart, secondary sex organs, and the brain
    • Causes -  decreased workload, use, pressure, blood supply, nutrition, hormonal stimulation, or nervous stimulation
  2. Cellular adaptation
    Increase in the size of cells
    • Hypertrophy
    • Can effect heart, kidneys
    • Caused by increased stimulation and demand
  3. Cellular adaptation
    Abnormal changes in the size, shape, and organization of mature cells
    • Dysplasia
    • Effect smooth muscle, frequently epithelial tissue of cervix and respiratory tract. 
  4. Cellular adaptation
    Reversible replacement of one mature cell by another, sometimes less differentiated cell type. 
    • Metaplasia
    • Can be caused by chronic injury or irritation
    • Example is cells of bronchial lining by stratisfied squamous epithelial cells.  These cells do not secrete mucous or have cilia, causing loss of bital protective mechanism. 
  5. Cellular adaptation
    An increase in the number of cells resulting from an increased rate of celluar division. 
    • Hyperplasia
    • Compensatory hyperplasia - allows organs to regenerate
    • Hormonal hyperplasia - allows endometrium of uterus to grow and thicken for reception of fertilized ovum. (pregnancy).  
  6. Review the steps of hypoxic injury to the myocardium
    • 1) Within 1 minute, heart becomes pale and has difficulty contracting
    • 2) 3-5 minutes, ceases to contract
    • 3) Abrupt lack of contraction is cuased by a rapid decrease in mitochondrial phosphorylation
    • 4) Insufficient ATP production
    • 5) Lack of ATP leads to increase in anearobic metabolism
    • 6) ATP then generated from glycogen (stored energy)
    • 7) When glycogen depleted, even anaerobic metabolsim stops. 
  7. Explain the NA-K+ action with hypoxia
    See. page 53.
    • Reduction of ATP levels causes plasma membrane's NA+-K+ pump and Na+-Ca++ exchange to fail
    • Intracellular accumuilation of Na+ and Ca++ and diffusion K+ out of the cell.  
    • Na+ and H20 then can enter the cell freely
    • Cellular swelling results.  
  8. An electrically uncharged atom or group of atoms having an unpaired electron is what?
    Free Radical
  9. What is the concern with free radicals?
    • Having one unpaired electron makes the molecule unstable
    • To stabilize, it gives up an electron to another molecule, or steals one
    • Therefore it is capable of injurious chemical bond formation with protiens, lipids, carbohydrates - keey molecules in membranes and nucleic acids.  
  10. What is the primary site of damage from a free radical in a cell
    Mitochondrial DNA
  11. How can free radicals be reduced with antioxidants?
    • 1) Spontaneous decay of superoxide to H20 and H202 (hydrogen peroxide)
    • 2) Antioxidants - vitamins A, C, E Sellenium
  12. Describe the cellular response to injury
    • 1) Loss of ATP retards sodium-potassium pump
    • 2) Disruption of transport mechanisms across cell memberane
    • 3) Reduction or cessation of cellular metabolism
    • 4) Water collects in vacoules of the ER
    • 5) Damage to lysosomal membrane
    • 6) Cellular death
    • 7) Phagocytosis of WBC
  13. Describe injury by carbon monoxide
    Carbon has 300 times binding capactiy to hemoglobin which prevents oxygen binding to hgb
Card Set
Cellular Injury
Mechanisms of cellular injury