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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
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Cellular adaptation
Increase in the size of cells
- Hypertrophy
- Can effect heart, kidneys
- Caused by increased stimulation and demand
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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.
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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.
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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).
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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.
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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.
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An electrically uncharged atom or group of atoms having an unpaired electron is what?
Free Radical
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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.
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What is the primary site of damage from a free radical in a cell
Mitochondrial DNA
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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
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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
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Describe injury by carbon monoxide
Carbon has 300 times binding capactiy to hemoglobin which prevents oxygen binding to hgb
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