Regulating the Internal Regulating the Internal EnvironmentEnvironment

HomeostasisHomeostasisBody TemperatureBody Temperature

Water BalanceWater BalanceMetabolic Waste DisposalMetabolic Waste Disposal

Homeostasis OverviewHomeostasis Overview

Regulators – internal change is Regulators – internal change is moderated in a changing environment moderated in a changing environment e.g. birdse.g. birds

Conformers – allow internal change with Conformers – allow internal change with certain external changescertain external changes

Budget = balance of loss and gain, Budget = balance of loss and gain, animals are open systems e.g. water animals are open systems e.g. water maintenance via intake overcomes losses maintenance via intake overcomes losses via breathing, sweating, urination, etc.via breathing, sweating, urination, etc.

QQ1010 Effect Effect

The multiple by which a particular The multiple by which a particular enzymatic reaction or overall metabolic enzymatic reaction or overall metabolic process increases with a 10process increases with a 10°°C C temperature change in the body.temperature change in the body.

For example, if the hydrolysis of For example, if the hydrolysis of amylose into maltose is 3.7 times amylose into maltose is 3.7 times greater at 25greater at 25°°C than at 15C than at 15°°C in fire belly C in fire belly toads, the Qtoads, the Q1010 is 3.7 for that reaction. is 3.7 for that reaction.

Each animal has an optimal range of Each animal has an optimal range of temptemp

If it’s warmer, I

digest faster.

Heat LossHeat Loss

Conduction = direct transfer of heat Conduction = direct transfer of heat from cold water or hot rockfrom cold water or hot rock

Convection = transfer of heat by Convection = transfer of heat by movement, windmovement, wind

Radiation = emission of Radiation = emission of electromagnetic waves by all objects electromagnetic waves by all objects greater than absolute zero, sungreater than absolute zero, sun

Evaporation = water needs a lot of Evaporation = water needs a lot of energy to evaporate, sweat, humidityenergy to evaporate, sweat, humidity

Ectotherms vs EndothermsEctotherms vs Endotherms

Ectotherms have such low metabolic Ectotherms have such low metabolic rates that they rely mostly on the rates that they rely mostly on the environment to determine their environment to determine their body tempbody temp

Endotherms have such high Endotherms have such high metabolic rates that body temp is metabolic rates that body temp is higher than the environmenthigher than the environment

Endotherms have an advantage, but Endotherms have an advantage, but it is costly!it is costly!

ThermoregulationThermoregulation

Insulation – many organisms have fat Insulation – many organisms have fat as an insulator.as an insulator.

Vasodilation vs vasoconstrictionVasodilation vs vasoconstriction Countercurrent heat exchange – Countercurrent heat exchange –

minimize heat loss in the extremities minimize heat loss in the extremities by allowing for close proximity of by allowing for close proximity of arteries and veins – venous blood is arteries and veins – venous blood is warmed by arterial blood as it re-warmed by arterial blood as it re-enters the body from the limbs.enters the body from the limbs.

Thermoregulation Cont.Thermoregulation Cont.

Evaporative heat loss cools Evaporative heat loss cools terrestrial animals.terrestrial animals.

Behavioral responses – basking in Behavioral responses – basking in the sun, warm rocks, find shade, the sun, warm rocks, find shade, enter cool water, hibernation, enter cool water, hibernation, migrationmigration

Change in metabolic rate - Change in metabolic rate - endothermsendotherms

Mammals and BirdsMammals and Birds

Heat can be increased by movement Heat can be increased by movement of muscles including shivering.of muscles including shivering.

NST – nonshivering thermogenesis – NST – nonshivering thermogenesis – certain animals have mitochondria certain animals have mitochondria that increase their metabolic activity that increase their metabolic activity to produce heat instead of ATPto produce heat instead of ATP

InsulationInsulation Sweating, panting, Sweating, panting,

Amphibians and ReptilesAmphibians and Reptiles

Temperature controlled mostly by Temperature controlled mostly by behaviorbehavior

Some extras: bull frogs secrete Some extras: bull frogs secrete mucous, marine iguanas of the mucous, marine iguanas of the Galapagos – vasoconstriction, female Galapagos – vasoconstriction, female pythons “shiver” to become pythons “shiver” to become endothermic when incubating eggsendothermic when incubating eggs

Dinosaurs?Dinosaurs?

Fish!Fish! Most are ectotherms Most are ectotherms

except for a few large except for a few large active fish such as the active fish such as the great white shark, great white shark, swordfish and bluefin swordfish and bluefin tuna. They maintain a tuna. They maintain a countercurrent countercurrent exchange with large exchange with large arteries full of cold blood arteries full of cold blood from the gills entering from the gills entering tissues just below the tissues just below the skin. Branches deliver skin. Branches deliver oxygenated blood to oxygenated blood to deep muscles.deep muscles.

InvertebratesInvertebrates

Most are ectothermsMost are ectotherms Some flying insects are endotherms – Some flying insects are endotherms –

Hawk moth, bumblebees, honey bees – Hawk moth, bumblebees, honey bees – they use flight muscles to generate heatthey use flight muscles to generate heat

Bumble bee queens can us Bumble bee queens can us countercurrent exchange to allow heat countercurrent exchange to allow heat to release to release

from the thorax and incubate eggs.from the thorax and incubate eggs. Bumble bees also huddle Bumble bees also huddle

Feedback MechanismsFeedback Mechanisms

Thermoregulation – see teachers flow Thermoregulation – see teachers flow chart.chart.

AcclimatizationAcclimatization

Endotherms - insulation layerEndotherms - insulation layer Ectotherms – metabolic processes – Ectotherms – metabolic processes –

enzymes may have different forms at enzymes may have different forms at different times of the year = different times of the year = temperature, cellular membranes temperature, cellular membranes may have a higher concentration of may have a higher concentration of unsaturated fats based on tempunsaturated fats based on temp

““antifreeze” - prevents ice antifreeze” - prevents ice crystalization in fish, frogs, crystalization in fish, frogs, arthropods and their eggsarthropods and their eggs

Heat shock ProteinsHeat shock Proteins

Found mostly in tissue culture, they Found mostly in tissue culture, they are proteins that maintain the are proteins that maintain the stability of other proteins, keep them stability of other proteins, keep them from denaturing in either stress or from denaturing in either stress or heat. Found in yeast, bacteria, plant heat. Found in yeast, bacteria, plant cells and animal cells!cells and animal cells!

TorporTorpor

Physiological state of inactivityPhysiological state of inactivity HibernationHibernation EstivationEstivation

OsmoregulationOsmoregulation

Management of the body’s water Management of the body’s water content and solute(salt) content.content and solute(salt) content.

Transport EpitheliumTransport Epithelium

Layer or layers of Layer or layers of specialized specialized epithelial cells that epithelial cells that regulate solute regulate solute movement.movement.

Prevalent in marine Prevalent in marine birds and ocean birds and ocean fish. Remove salt fish. Remove salt to maintain water to maintain water balance.balance.

Nitrogenous WastesNitrogenous Wastes

Ammonia – common in aquatic species, Ammonia – common in aquatic species, lost from epithelial tissue of gills, lost from epithelial tissue of gills, kidneys relatively inactive. In freshwater kidneys relatively inactive. In freshwater exchange of Na+ into cells and NHexchange of Na+ into cells and NH44+ + out.out.

Urea – produced by liver, less toxic than Urea – produced by liver, less toxic than , water soluble NH , water soluble NH44, organisms use , organisms use energy to make and lose water to energy to make and lose water to remove it. Amphibians probably switch.remove it. Amphibians probably switch.

N waste continuedN waste continued

Uric acid – land snails, insects, birds Uric acid – land snails, insects, birds and many reptilesand many reptiles

Even less toxic than urea and can be Even less toxic than urea and can be excreted with less water loss as a excreted with less water loss as a semisolid paste.semisolid paste.

Costs more energy than ureaCosts more energy than urea Build up of urea in an egg may be Build up of urea in an egg may be

toxictoxic

Osmotic BalanceOsmotic Balance

Over time the uptake and removal of Over time the uptake and removal of water must balance in all animals.water must balance in all animals.

Remember what happens to an Remember what happens to an animal cell in salt water or distilled animal cell in salt water or distilled water?water?

OsmoregulatorOsmoregulator

Animal that must continually adjust Animal that must continually adjust its internal osmolarity because it is its internal osmolarity because it is not the same as its environment.not the same as its environment.

OsmoconformerOsmoconformer

Animal’s inner osmolaritly is equal to Animal’s inner osmolaritly is equal to its surroundings – isoosmoticits surroundings – isoosmotic

I’m the only vertebrate that is

an osmoconformer!

You are one ugly

hag!

Fish have special problemsFish have special problems

Marine fish have the dilemma or too much Marine fish have the dilemma or too much salt and possible water loss via direct salt and possible water loss via direct contact with water and gill epithelial cells.contact with water and gill epithelial cells.

They excrete excess salt via gills and They excrete excess salt via gills and scant urine. Obtain water from gills and scant urine. Obtain water from gills and food.food.

Chondricthyes have a rectal gland that Chondricthyes have a rectal gland that removes salt – special organremoves salt – special organ

Freshwater fish excrete large amounts of Freshwater fish excrete large amounts of water through very dilute urine.water through very dilute urine.

AnhydrobiosisAnhydrobiosis

Some arthropods and rotifers can Some arthropods and rotifers can survive for many years in a dried out survive for many years in a dried out statestate

Excretory SystemsExcretory Systems

Selective reabsorption – body Selective reabsorption – body accumulates fluid, and maintains accumulates fluid, and maintains water balance through reabsorption water balance through reabsorption of some solutes and secretion of of some solutes and secretion of others.others.

Fluid is accumulated by filtration – Fluid is accumulated by filtration – blood pressure or hydrostatic blood pressure or hydrostatic pressure accumulate the nitrogenous pressure accumulate the nitrogenous waste.waste.

ProtonephridiaProtonephridia

Network of dead-end tubules lacking Network of dead-end tubules lacking internal openings. They branch internal openings. They branch through the body with the smallest through the body with the smallest ones capped by a flame bulb.ones capped by a flame bulb.(Osmoregulation mostly)(Osmoregulation mostly)

It has a tuft of cilia that draws the It has a tuft of cilia that draws the water out of the tubule to the outside.water out of the tubule to the outside.

Most of metabolic waste is removed Most of metabolic waste is removed via diffusion.via diffusion.

MetanephridiaMetanephridia

Internal openings that collect body Internal openings that collect body fluids and remove it via cilia.fluids and remove it via cilia.

Found in most Annelids – earthworms Found in most Annelids – earthworms have two per segment. have two per segment.

Remove nitrogenous waste and Remove nitrogenous waste and osmoregulate as well.osmoregulate as well.

Malphigian tubules Malphigian tubules

Insects and other terrestrial Insects and other terrestrial arthropodsarthropods

Removes nitrogenous waste and Removes nitrogenous waste and maintains water balance.maintains water balance.

Collects and then leads to rectum. Collects and then leads to rectum. Most of the water is reabsorbed into Most of the water is reabsorbed into the hemolymph and waste is the hemolymph and waste is secreted with feces.secreted with feces.

The Kidney!The Kidney!

A = Blood, arteries A = Blood, arteries and veinsand veins

B = Renal CalyxB = Renal Calyx C = UreterC = Ureter D = Renal MedullaD = Renal Medulla E = Renal CortexE = Renal Cortex Label animation for Label animation for

nephronnephron

Step by step animationStep by step animation