BIO%20203.09%20Lecture%204s

BIO 203.09 Lectu - BIO 203 Lecture 4 Temperature Regulation Prof William Collins Office 534 Life Sciences Building Office Hours Mondays 9:00 10:00

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1 BIO 203: Lecture 4 - Temperature Regulation Prof. William Collins Office: 534 Life Sciences Building Office Hours: Mondays, 9:00 - 10:00 PM (on-line) Tuesdays, 11:30 AM - 12:30 PM Thursdays, 4:00 - 5:00 PM Heterotherms Animals capable of varying degrees of endothermic heat production. Temporal Heterotherms - T B varies over time • hibernation, topor (hummingbirds), T B fluctuations during the day (camels) Regional Heterotherms - different parts of body at different temperatures • ectotherms that can maintain core temperature higher than ambient temperature (tuna, large sharks) • testes in some mammals (canine, humans)
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2 Figure 40.16 Thermoregulation in large, active fishes Thermoregulation in Endotherms T amb MR BMR As T amb gets colder, MR increases to produce heat and maintain T B . TZ Sweating requires energy Vasodilation / Vasoconstriction vasodilation vasoconstriction Behavioral Thermoregulation Metabolic Rate
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Endotherms In The Cold MR Heat production Energetically Costly Thermogenesis : convert chemical energy into heat Shivering Thermogenesis - muscle contraction to produce heat. • Groups of antagonistic muscles are activated - little net movement other than shivering. • Muscle contraction is only 25% efficient - 75% of energy expended is released as heat. Nonshivering Thermogenesis - metabolism of fat to produce heat. • Very little energy is conserved in the form of ATP. Endotherms In The Cold Brown Fat (brown adipose tissue (BAT)) A specialization for fat-fueled thermogenesis Found in mammals (e.g., bats) usually in neck and between shoulders Adaptation for rapid, massive heat production • Heats up very quickly
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This note was uploaded on 02/24/2009 for the course BIO 203 taught by Professor Johncabot during the Spring '08 term at SUNY Stony Brook.

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BIO 203.09 Lectu - BIO 203 Lecture 4 Temperature Regulation Prof William Collins Office 534 Life Sciences Building Office Hours Mondays 9:00 10:00

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