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Thermoregulation. Ecto/Endotherms. Differences are based on source of body heat Which has a higher metabolic rate at cold temperatures, ectotherms or endotherms? Endotherms. Mechanisms of Thermoregulation:. Insulation
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Ecto/Endotherms • Differences are based on source of body heat • Which has a higher metabolic rate at cold temperatures, ectotherms or endotherms? • Endotherms
Mechanisms of Thermoregulation: • Insulation • Circulatory adaptations (vasodilatation when very hot and vasoconstriction when cold) • Arteries and veins run countercurrent • Evaporative heat loss • Behavioral responses • Endotherms can regulate metabolic heat porduction
Skin as organ of thermoregulation How does brown fat help with heat production?
Transport Epithelia • What is the importance of transport epithelia to the process of osmoregulation? • Form selectively permeable barrier • Regulate solute movements • e.g. salt excreting glands in birds • Why are most transport epithelia arranged in tubular networks? • Increase surface area
Nitrogenous Wastes What is the purpose of digesting amino acids?
Osmoregulators/Osmoconformers • What is the difference between an osmoregulator and an osmoconformer? • Osmoconformers are isotonic with environment • Osmoregulators adjust internal osmolarity • Water balance in water • Water balance on land involves adaptations to conserve water.
Excretory Systems • Filtration, reabsorption and secretion are key functions of excretory systems • Invertebrate Excretory Systems: • Protonephridia/Falme cells in flatworms • Metanephridia in eartworms • Malphighian tubules of insects • Mammalian kidney….
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Why are there two hormonal pathways for osmoregulation? • RAAS – detects changes in blood volume without changing osmolarity. Such as: diarrhea, injury … • ADH – detects changes in osmolarity • Such as: excessive sweating, failure to drink enough…
ANF • Atrial natriuretic factor, (ANF) – opposes RAAS • Walls of atria release ANF in response to increase in blood volume • ANF inhibits release of renin from JGA.
Vetebrate Kidney Adaptations • What does a lot of juxtamedulary nephrons indicate about the lifestyle of that animal? • What do shorter loops of Henle indicate?