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9 Cards in this Set
- Front
- Back
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Enzymes that protect the lens from oxidative stress |
glutathione peroxidase catalases supraoxide desmutase |
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when is the Hexose monophosphate shunt stimulated |
high concentrations of glucose |
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examples of gap junctions between lens fibres |
connexins - allow cell to cell transport of small molecules N-cadherin - lateral cell to cell transport of larger molecules |
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what is the normal lens hydration, Na and K |
66% hydration Na - 20mM K - 120-125mM (maintained by NaK ATPase pump) |
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Pump Leak Theory |
Combination of the active transport and membrane permeability K and various other molecules are transported actively at anterior surface and diffuse via a concentration gradient out of permeable posterior surface |
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what is the primary structural protein of the zonules |
Fibrillin |
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what are the defects in pseudoexfoliation, pearson syndrome and alport syndrome |
Lysine oxidase laminin Beta2 Collagen type IV |
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pathophysiology if nuclear cataracts |
increase in protein aggregation leading to increase scattering of light related to increase oxidative stress - decrease rate of glutathione diffusion to nucleus |
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Pathophysiology of sugar cataracts |
High glucose concentrations > activation of the sorbitol pathway > polyol dehydrogenase (converts sorbitol to fructose) has relative low affinity > sorbitol accumulation > ^osmotic pressure > swelling of fibres and disruption of cytoskeletal structure |
