Term
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Definition
| body temperature is regulated by the extrenal environment |
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Term
| temperature regulation in sharks |
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Definition
- ectothermic
- heat diffuses through body 10x faster than water
- gills keep blood temps same as environment
- heat from metabolism is lost through the gills
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Term
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Definition
- keep body temp higher than water
- 7 lamnids: great white, mako, porbeagle, thresher, salmon sharks
- whole body
- regional
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Term
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Definition
- elevated temps due to rete mirable
- blood supply is rerouted so arterioles are next to veins
- heat diffuses from veins to arterioles
- counter current exchange
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Term
| whole body endothermy circulation |
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Definition
- routs blood into two cutaneous artries that run along side of body. a cutaneous vein (along artery) brings blood back to the heart
- heat transfered from venous blood to arterial blood
- blood travels into muscles though arterial and venous capillaries
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Term
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Definition
- maintains highest temperatures
- has been measured with body temps as high as 14 C above ambient water temps
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Term
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Definition
- isolated elevated temps
- eye, brain, and parts of digestive tract
- same concept as whole body, but on a smaller scale
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Term
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Definition
- increase muscle power
- increases sustained swimming
- can invade other habitats
- more O2 for working tissues
- keeps brain alert in cold water
- increased lactate clearence
- increased digestive efficiency
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Term
| disadvantages of endothermy |
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Definition
- high BMR- energetically costly (10x higher compared to similarly sized ectothermic sharks)
- aquire more food
- population densities are not as high as for ectothermic species due to competition
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