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Unformatted text preview: close contact with veins carrying cool blood from periphery 2 Near the end of the leg cooled arterial blood can still transfer heat to the even colder blood in adjacent vein 3 As blood in veins returns to the body core it is now warmed, retaining heat and minimizing heat loss 6. The body's thermostat in endothermic mammals is a group of nerve cells located in the hypothalamus of the brain: Hypothalamus is capable of initiating two thermoregulatory mechanisms: 1)heat conserving mechanisms e.g. vasoconstriction, piloerection, shivering and nonshivering thermogenesis 2) heat releasing mechanisms e.g. vasodilation and sweating 7. Living with cold: Hibernation Types of dormancy: Hibernation, Torpor, Winter sleep, Carnivore lethargy, Estivation Hibernators : Chipmunks, Squirrels, Bats, Skunks, Garter snakes, Bull frogs Hibernation: abandoning maintenance of high Tb but not abandoning homeostasis (Fig. a0.21)...
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- Fall '10