Thermoregulation

by airby sunlight

direct contact

Ecto/EndothermsEcto/Endotherms

Differences are based on source Differences are based on source of body heatof body heat

Which has a higher metabolic Which has a higher metabolic rate at cold temperatures, rate at cold temperatures, ectotherms or endotherms?ectotherms or endotherms?

EndothermsEndotherms

Mechanisms of ThermoregulationMechanisms of Thermoregulation::

InsulationInsulationCirculatory adaptations (vasodilatation Circulatory adaptations (vasodilatation when very hot and vasoconstriction when when very hot and vasoconstriction when cold)cold)Arteries and veins run countercurrentArteries and veins run countercurrentEvaporative heat lossEvaporative heat lossBehavioral responsesBehavioral responsesEndotherms can regulate metabolic heat Endotherms can regulate metabolic heat productionproduction

Skin Provides Protection and Thermoregulation

Transport EpitheliaTransport EpitheliaWhat is the importance of transport What is the importance of transport epithelia to the process of epithelia to the process of osmoregulation?osmoregulation?

Form selectively permeable barrierForm selectively permeable barrier

Regulate solute movementsRegulate solute movements

e.g. salt excreting glands in birdse.g. salt excreting glands in birds

Why are most transport epithelia Why are most transport epithelia arranged in tubular networks?arranged in tubular networks?

Increase surface area Increase surface area

Salt-Excreting Glands in Marine Birds

Osmoregulation-

How animals regulate soluteconcentrations and balance the gain and loss of water

OsmoconformersOsmoconformers are isotonic with are isotonic with environment Ex: most marine invertsenvironment Ex: most marine inverts

OsmoregulatorsOsmoregulators adjust internal adjust internal osmolarity Ex: marine vertebrates and osmolarity Ex: marine vertebrates and some marine invertssome marine inverts

Water balance on land involves Water balance on land involves adaptations to conserve water.adaptations to conserve water.

Flatworm (Planaria)

EarthwormMetanephridia

Metanephridium

MalpighianTubules of Insects

Variation in Nitrogenous Wastes

ExcretoryOrgans

Kidney Cross Section

NephronStructure

NephronStructure

Secretion Secretion

Reabsorption

Filtration

Proximal Convoluted Tubule – high pressure filters H2O, urea, vitamins, salts, and glucose into Bowman’s Capsule from the glomerulus; where most reabsorption occurs into peritubular capillaries; secretion of H+ and NH3 occurs

Loop of Henle - creates high concentration of NaCl promoting the reabsorption of H2O; countercurrent flow leads to a more concentrated urine

Distal Convoluted Tubule – regulates K+ and NaCl concentration; toxic wastes reabsorbed into the filtrate forming urine

Osmolarity increases as solutes become more concentrated in millosmoles (moles of solute/L of solution)