生物心理学 PPT课件版 Chapter 09：Homeostasi：Active Regulation of Internal States

Chapter

9：Homeostasi：ActiveRegulationofInternalStates主讲：潘晓红华东师范大学心理与认知科学学院xhpan@

Biological

PsychologyHomeostasisMaintainsInternalStateswithinaCriticalRangeWarmthwaterFoodThesesystemsshowredundancy–aremonitoredbymorethanonemechanism.

—Thisredundancyhelpskeepusalive,butitalsomakesitdifficultforustofigureouthowthebodyregulatestemperature,waterbalance,andfoodintake.Systemsexploittheorganism’sbehaviorstokeepthemselvesbalanced.

—The

animal

is

showing

motivated

behaviorNegativeFeedback

systemsaretheprimaryhomeostaticmechanisms

.

Ifadesiredvalue,thesetpoint,isdeviatedfrom,compensatoryactionbegins.

.

Thesetzonereferstotherangeoftoleranceinasystem.HomeostasisMaintainsInternalStateswithinaCriticalRangeUnavoidableLossesRequireUstoGainHeat,Water,andFoodContents:

TemperatureRegulationFluidRegulationFoodandEnergyRegulationTemperatureRegulationBodyTemperatureisaCriticalConditionforAllBiologicalProcessSomeAnimalsGenerateHeat;OthersMustObtainHeatfromtheEnvironmentWhichBehaviorsCanAdjustBodyTemperature?TheBrainMonitorsandRegulatesBodyTemperature一.

BodyTemperatureisaCriticalConditionfor AllBiologicalProcessAs

the

interior

of

a

cell

cools,

chemical

reactions

slow

down,andsomestopaltogether→bilipid(双脂肪)

layers

that

make

up

cellular

membranes

become

so

disrupted

by

the

formation

of

ice

molecules

that

cannot

re-form

even

when

thawed.→some

animals

that

cannot

avoid

subfreezing

T

produce

“antifreeze”

consisting

of

special

protein

molecules

that

disrupt

the

formation

of

ice

crystals

and

prevent

damage

to

membranes.一.

BodyTemperatureisaCriticalConditionforAllBiologicalProcessAs

the

interior

of

a

cell

cools,

chemical

reactions

show

down,

and

some

stop

altogether.At

high

T,

protein

molecules

fold

together

improperly

and

thus

do

not

function

as

they

should.

→

the

amino

acids

begin

to

break

apart

and

fuse

together

more

or

less

random,

so

can

say

the

tissue

is

fixed

(cooked)

→

brain

cells

are

especially

sensitive

to

high

T.TemperatureRegulationBodyTemperatureisaCriticalConditionforAllBiologicalProcessSomeAnimalsGenerateHeat;OthersMustObtainHeatfromtheEnvironmentWhichBehaviorsCanAdjustBodyTemperature?TheBrainMonitorsandRegulatesBodyTemperature

二.

SomeAnimalsGenerateHeat;Others

Must ObtainHeatfromtheEnvironmentCold-blooded

&

Warm-blooded

?

Homeotherms

&

poikilotherms?

Endotherms

&

Ectotherms

?

Endotherms

(from

the

Greek

endon,

“within”)

regulate

their

body

temperature

chiefly

by

internal

metabolic（新陈代谢的）processes.Ectotherms

(from

the

Greek

ektos,

“outside”)

get

most

of

their

heat

from

the

environment.

二.

SomeAnimalsGenerateHeat;Others

Must ObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costCost:

Much

food

must

be

obtained

and

metabolizedElaborate

regulatory

systems

are

requiredDepartures

of

body

T

of

a

few

degrees

in

either

direction

impair

functioning

二.

SomeAnimalsGenerateHeat;Others

Must ObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costCost:

Benefit:increased

capacity

to

sustain

a

high

level

of

muscular

activity

over

prolonged

periods

二.

SomeAnimalsGenerateHeat;Others

Must ObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costEndotherms

generate

heat

through

metabolismThe

rate

of

heat

production

can

be

adjusted

to

suit

conditions.A

more

conspicuous

way

to

generate

heat

is

through

muscular

activity—shiver.

二.

SomeAnimalsGenerateHeat;Others

MustObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costEndotherms

generate

heat

through

metabolismEctothermsregulatebodytemperature

bybehavior.

二.

SomeAnimalsGenerateHeat;Others

MustObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costEndotherms

generate

heat

through

metabolismEctothermsregulatebodytemperature

bybehavior.Body

size

and

shape

affect

heat

production

and

heat

lossAhighsurface-to-volumeratiomeansagreatercapacitytodissipateheat.5.

Body

size

and

shape

affect

heat

production

and

heat

lossHeatisexchangedwiththeenvironmentprimarilyatthesurfaceofthebody→Ahighsurface-to-volumeratiomeansagreatercapacitytodissipateheat.→SmallmammalstendtomaintainbodyTslightlyhigherthanthoseoflargemammals,andtheyloseheatmoreeasilythanlargermammalsdo.→Inthedistributionofspeciesacrossenvironmentscanevidenttheeffect

(e.g.thoselivingincoldclimatesarelargerthanthoseinwarmenvironments).Body

size

and

heat

production

of

some

birds

and

mammalsEnergy

output

per

daySpeciesBody

weight

(kg)Body

Surface

(m2)Surface-to-weight

ratio

(m2/kg)Total

(kcal)Per

unit

of

body

weight

(kcal/kg)Per

unit

of

body

surface

(kcal/m2)Canary0.0160.0060.3755310760Rat0.20.030.1525130830Pigeon0.30.040.1330100670Cat3.00.20.0715050750Human601.70.03150025850Elephant3600240.00747000132000Heatisexchangedwiththeenvironmentprimarilyatthesurfaceofthebody.Shapealsoaffectstheconservationofheatandthereforeenergy.→ThemorecompactbodyconservesheatbetterandthereforeisbetterabletoprotectitsinternalTinacoldclimate(e.g.Inhuman,taller,moreslenderbodyformshaveevolvedintheTropics,andshorter,stockierphysiquesaremoretypicalofcolderregion;Inanimal,bodyappendagessuchastheearsaresmallerinarcticspeciesthaninrelatedtropicalspecies..Body

size

and

shape

affect

heat

production

and

heat

lossInhuman,taller,moreslenderbodyformshaveevolvedintheTropics,andshorter,stockierphysiquesaremoretypicalofcolderregion;FoxesTropicalTemperateArcticBody

size

and

shape

affect

heat

production

and

heat

lossHeatisexchangedwiththeenvironmentprimarilyatthesurfaceofthebody.Shapealsoaffectstheconservationofheatandthereforeenergy.Furofmammalsandfeathersofbirdsarespecialadaptationsoftheskinthatinsulatethebodyfromtheenvironment.→spendagreatdealoftimegrooming,andpreening

二.

SomeAnimalsGenerateHeat;Others

Must ObtainHeatfromtheEnvironmentEndotherms

&

EctothermsThe

advantages

of

endothermy

come

at

a

costEndotherms

generate

heat

through

metabolismEctothermsregulatebodytemperature

bybehavior.Body

size

and

shape

affect

heat

production

and

heat

lossLose

heat,

different

species

have

different

adaptation

of

doing

so.TemperatureRegulationBodyTemperatureisaCriticalConditionforAllBiologicalProcessSomeAnimalsGenerateHeat;OthersMustObtainHeatfromtheEnvironmentWhichBehaviorsCanAdjustBodyTemperature?TheBrainMonitorsandRegulatesBodyTemperature三.

WhichBehaviorsCanAdjustBody Temperature?Changing

exposure

of

the

body

surface

—

e.g.

by

huddling

or

extending

limbsAniguanawilllieonawarmrocktoraiseitstemperature.Itliesbroadsidetothesununtilitstemperaturereaches37°,thenturnstofacethesuntoabsorblessheat.三.

WhichBehaviorsCanAdjustBody Temperature?Changing

exposure

of

the

body

surfaceChanging

external

insulation—e.g.

by

using

clothing

or

nest.Selecting

a

surrounding

that

is

less

thermally

stressful—e.g.

by

moving

to

the

shade

or

into

a

burrowYoung

birds

and

mammals

need

help

to

regulate

body

temperaturePhysiologicalPhysiological

Thermoregulation:

Newbornratsusebrown-fatdepositstogenerateheat三.

WhichBehaviorsCanAdjustBody Temperature?Changing

exposure

of

the

body

surfaceChanging

external

insulationSelecting

a

surrounding

that

is

less

thermally

stressfulYoung

birds

and

mammals

need

help

to

regulate

body

temperaturePhysiologicalsocialthermoregulationSocial

Thermoregulation:huddletogetherAnesthetizedpupremainsinthecoreandbecomesoverheatedAnesthetizedpupispushedtoperipheryandbecomestoocool.三.

WhichBehaviorsCanAdjustBody Temperature?Changing

exposure

of

the

body

surfaceChanging

external

insulationSelecting

a

surrounding

that

is

less

thermally

stressfulYoung

birds

and

mammals

need

help

to

regulate

body

temperatureSome

endotherms

survive

by

letting

their

body

T

plummet—torpor

(蛰伏)TemperatureRegulationBodyTemperatureisaCriticalConditionforAllBiologicalProcessSomeAnimalsGenerateHeat;OthersMustObtainHeatfromtheEnvironmentWhichBehaviorsCanAdjustBodyTemperature?TheBrainMonitorsandRegulatesBodyTemperature四.TheBrainMonitorsandRegulates BodyTemperatureExperiments

––

anterior

hypothalamus

,

preoptic

area(POA)Lesion

experimentsregulation

by

locomotor

and

other

behaviors

common

to

both

endotherms

and

ectotherms;Lesionsinthelateralhypothalamus(LH)abolishbehavioralregulation（行为调节）,butdonotaffectphysiologicalresponsessuchasshivering四.TheBrainMonitorsandRegulates BodyTemperatureExperiments

––

anterior

hypothalamus

,

preoptic

area(POA)Lesion

experimentsregulation

by

locomotor

and

other

behaviors

common

to

both

endotherms

and

ectotherms;physiological

regulation

characteristic

of

endothermsPhysiologicalresponsesareimpairedbylesionstothepreopticarea(POA),withoutdisruptionofbehavior.四.TheBrainMonitorsandRegulates BodyTemperatureExperiments

––

anterior

hypothalamus

,

preoptic

area(POA)Lesion

experimentsReceptors

at

the

surface

of

body

also

monitor

temperature—shiver/sweatDose

the

body

have

a

single

master

thermostat(温度调节装置)?4.

Dose

the

body

have

a

single

master

thermostat

?A

hierarchy

of

thermoregulatory

circuitsSpinal

levelMidbrainHypothalamus

(including

the

POA)→Thermoneutral

（热平衡的）zones

of

thermoregulatory

systems

are

narrower

at

higher

levels

of

the

nervous

system

than

at

lower

levelsThe

Basic

thermoregulatory

system:AfferentsSkin

surfaceBody

corehypothalamusNeural

regionsSpinal

cordBrainstemhypothalamusEffectorsBehavioral

responsesShiveringHeat

seeking/avoiding

BehaviorsAutonomic

responsesVasoconstriction/dilationSweatingRespirationBrown-fat

stimulationThyroid

hormone

secretionContents:

TemperatureRegulationFluidRegulationFoodandEnergyRegulationFluidRegulationOur

Cells

Evolved

to

Function

in

SeawaterTwo

Internal

Cues

Trigger

ThirstHomeostatic

Regulation

of

Salt

is

Required

for

Effective

Regulation

of

Water一.OurCellsEvolvedtoFunctionin SeawaterThe

first

living

creatures

on

Earth

arose

in

the

sea.Land

animals

had

to

prevent

dehydration

so

that

their

cells

would

work

properly.They

needed

a

more

or

less

watertight

outer

layer

of

cells,

and

they

had

to

maintain

the

proper

concentration

of

salts

and

other

molecules

in

body

fluids一.OurCellsEvolvedtoFunctionin SeawaterThe

first

living

creatures

on

Earth

arose

in

the

sea.We

must

relinquishing

and

replacing

the

body’s

water,

so

must

monitor

and

regulate

the

composition

of

body

fluidAverage

Daily

Water

Balance

of

an

Adult

HumanSourceQuantity

(liters)Approximate

intake

Fluid

water1.2

Water

content

of

food1.0

Water

from

oxidation

of

food0.3

Total2.5Approximate

output

Urine1.4

Evaporative

lose0.9

Feces0.2

Total2.5一.OurCellsEvolvedtoFunctionin SeawaterThe

first

living

creatures

on

Earth

arose

in

the

sea.We

must

relinquishing

and

replacing

the

body’s

water,

so

must

monitor

and

regulate

the

composition

of

body

fluidWater

in

the

human

body

moves

back

and

forth

between

two

major

compartmentsWater

in

the

human

body

moves

back

and

forth

between

two

major

compartmentsIntracellular

&

extracellular

compartment,

water

continually

migrates

between

themOsmosis

(渗透性)Semipermeable

(半透性的)Osmosis一.OurCellsEvolvedtoFunctionin SeawaterThe

first

living

creatures

on

Earth

arose

in

the

sea.We

must

relinquishing

and

replacing

the

body’s

water,

so

must

monitor

and

regulate

the

composition

of

bodyWater

in

the

human

body

moves

back

and

forth

between

two

major

compartmentsThe

extracellular

fluid

compartment

serves

as

a

buffer—areservoir（水库）FluidRegulationOur

Cells

Evolved

to

Function

in

SeawaterTwo

Internal

Cues

Trigger

ThirstHomeostatic

Regulation

of

Salt

is

Required

for

Effective

Regulation

of

Water二.TwoInternalCuesTriggerThirstHypovolemic(血量减少性)

thirst

is

triggered

by

a

loss

of

water

volumeBaroreceptors（压力感受器）—blood

pressure

dropsThe

role

of

vasopressin

(抗利尿激素)The

renin-angiotensin

(肾素-血管收缩素)

systemThesubfornicalorgan(SFO,穹窿下器)may

be

one

of

the

brain

sites

responding

to

angiotensin

II

by

triggering

thirst.TheAngiotensin(血管紧缩素)Cascade抗利尿激素醛固酮氨基肽酶肾素Theroleofvasopressin(抗利尿激素)二.TwoInternalCuesTriggerThirstHypovolemic

thirst

is

triggered

by

a

loss

of

water

volumeOsmotic

thirst

is

triggered

by

a

change

in

the

concentration

of

extracellular

fluid2.Osmotic

thirst

is

triggered

by

a

change

in

the

concentration

of

extracellular

fluidLossofwater(respiration,perspiration,urination)orintakeofsaltyfood.Waterispulledoutofcellstobalancetheconcentrationsoftheintra-andextracellularcompartmentsNeuronsspreadwidelythroughoutthePOA,anteriorhypothalamus,supraopticnucleus,andtheOVLT(organumvasculosumofthelaminaterminalis,终板血管器).IfvolumeislowIfsoluteconcentrationishigh穹窿下器孤束核抗利尿激素ADH视上核室旁核CircumventricularOrgans(室周器)最后区二.TwoInternalCuesTriggerThirstHypovolemic

thirst

is

triggered

by

a

loss

of

water

volumeOsmotic

thirst

is

triggered

by

a

change

in

the

concentration

of

extracellular

fluidWe

don’t

stop

drinking

just

because

our

throat

and

mouth

are

wetNormally

all

the

signals—blood

volume,

osmolality,

moisture

in

the

mouth,

estimates

of

the

amount

of

water

we’ve

ingested

that’s

“on

the

way”—register

agreenent,

but

the

cessation

of

one

signal

alone

will

not

stop

thirst;

in

this

way

animals

ensure

against

dehydration.FluidRegulationOur

Cells

Evolved

to

Function

in

SeawaterTwo

Internal

Cues

Trigger

ThirstHomeostatic

Regulation

of

Salt

is

Required

for

Effective

Regulation

of

Water三.HomeostaticRegulationofSaltisRequired forEffectiveRegulationofWaterWe

cannot

maintain

water

in

the

extracellular

compartment

without

solutes.The

number

of

Na+

ions

we

possess

primarily

determines

how

much

water

we

can

retain.Mineralocorticoid

(盐皮质激素),

induces

the

kidneys

to

conserve

Na+Contents:

TemperatureRegulationFluidRegulationFoodandEnergyRegulation“Wearedependentonfoodforenergyandforbuildingandmaintainingourbodiesthathungerisacompellingmotiveandflavorsarepowerfulreinforcements”“Theneedtoeatshapesourdailyschedulesandmoldsouractivities”“Ourbasicrelianceonfoodforenergyandnutritionissharedwithallotheranimals.”Contents:

NutrientRegulationRequirestheAnticipationofFutureNeedsInsulinisCrucialfortheRegulationofBodyMetabolismExperienceProtectsUsfromToxinsinFoodIsThereaSingleSatietyorHungerCenterintheBrainAnorexiaNervosaandBulimiaAreLife-ThreateningEatingDisorders一.

NutrientRegulationRequiresthe AnticipationofFutureNeedsFoodregulationiscomplicatedMostofOurFoodIsUsedtoProvideUswithEnergyCarbohydratesProvideEnergyforBodyandBrain1.

FoodregulationiscomplicatedFirstreasonforthegreatercomplexityisthatfoodisneedednotonlytosupplyenergybutalsotosupplynutrients.Nutrients

Nutrientsarechemicalsthatarenotusedassourcesofenergybutarerequiredfortheeffectivefunctioningofthebody(forgrowth,maintenance,repairofbodystructures).Wedonotknowallthenutritionalrequirementofthebody.

Aminoacids:ofthe20aminoacidsfoundinourbodies,9aredifficultorimpossibleforustomanufacture(—essentialaminoacids)Vitamins:15

Minerals:

several1.

FoodregulationiscomplicatedFirstreasonforthegreatercomplexityisthatfoodisneedednotonlytosupplyenergybutalsotosupplynutrients.Secondreasonisthatnoanimalcanaffordtorunoutofenergyornutrients;theremustbeareserveonhandatalltimes.Reserve

ReserveV.SMobility

HowtheorganismanticipatestheneedforenergyandnutrientsHowtheresourcesaremovedinandoutofvariousbodyreservoirs.digestion一.

NutrientRegulationRequirestheAnticipationofFutureNeedsFoodregulationiscomplicatedMostofOurFoodIsUsedtoProvideUswithEnergyCarbohydratesProvideEnergyforBodyandBrain2.

MostofOurFoodIsUsedtoProvide UswithEnergyAlltheenergyweneedtomove,think,breath,andmaintainbodytemperatureisderivedinthesameway:itisreleasedasthechemicalbondsofcomplexmoleculesarebrokentoformsmaller,simplercompounds.assesstheamountofenergyusedintermsofcalories.thecaloriesoffoodaredescribingthepotentialenergyavailable.metabolicrate(kilocaloriesperday,kcal/day)about75%oftheingestedenergybecameavailableforuseinbodyfunctions.2.

MostofOurFoodIsUsedtoProvide UswithEnergyAlltheenergyweneedtomove,think,breath,andmaintainbodytemperatureisderivedinthesameway:

TheavailableenergyisusedinoneofthreeactivitiesProcessingofnewlyingestedfood(8%)Basalmetabolism(55%)Activebehavioralprocesses(12~13%)2.

MostofOurFoodIsUsedtoProvide UswithEnergyAlltheenergyweneedtomove,think,breath,andmaintainbodytemperatureisderivedinthesameway:

Theavailableenergyisusedinoneofthreeactivities

Therateofbasalmetabolism

Therateofbasalmetabolism

MaxKleiber(1947)

this

rule

has

been

shown

to

apply

from

the

largest

mammals

to

mice.kcal/day=70×weight0.75The

relation

between

body

size

and

metabolism

Therateofbasalmetabolism

MaxKleiber(1947)

this

rule

has

been

shown

to

apply

from

the

largest

mammals

to

mice.

it

holds

across

species

but

not

within

species——body

weight

is

only

one

factor

affecting

metabolic

rate

within

a

species,

an

animal’s

basal

metabolic

rate

may

depart

significantly

from

the

value

predicted

by

Kleiber’s

equationkcal/day=70×weight0.752.

MostofOurFoodIsUsedtoProvide UswithEnergyAlltheenergyweneedtomove,think,breath,andmaintainbodytemperatureisderivedinthesameway:

Theavailableenergyisusedinoneofthreeactivities

Therateofbasalmetabolism

Why

losing

weight

is

so

difficultWhylosingweightissodifficult

Severe

restriction

of

caloric

intake

affects

metabolic

rate

much

more

than

it

affects

body

weight

organism

adjust

their

energy

expenditures

in

response

to

under-

or

overnutrition,

they

tend

to

resist

either

losing

or

gaining

weight.一.

NutrientRegulationRequires theAnticipationofFutureNeedsFoodregulationiscomplicatedMostofOurFoodIsUsedtoProvideUswithEnergyCarbohydratesProvideEnergyforBodyandBrain3.

CarbohydratesProvideEnergyfor BodyandBrain

Large

carbohydrate

molecules

can

be

broken

down

into

simple

carbohydrates.

Glucose

brain

is

dependent

on

glucose

for

energy.

the

body

can

use

both

glucose

and

more

complicated

molecules

(e.g.

fatty

acids)

for

energy.twoproteinhormonesfrompancreasGlucagon(胰高血糖素)InsulinTheydeterminethebalanceofreadyenergy(glucose)fromashort-termenergysource(glycogen).The

Role

of

Insulin

in

Energy

UtilizationThelong-termenergystorageContents:

NutrientRegulationRequirestheAnticipationofFutureNeedsInsulinisCrucialfortheRegulationofBodyMetabolismExperienceProtectsUsfromToxinsinFood

IsThereaSingleSatietyorHungerCenterintheBrainAnorexiaNervosaandBulimiaAreLife-ThreateningEatingDisorders二.

InsulinisCrucialfortheRegulation ofBodyMetabolismAnotherimportantroleofinsulinDiabeticsMellitusDespiteItsImportance,InsulinIsNottheSoleSignalforEitherHungerorSatiety1.

AnotherimportantroleofinsulinEnablingthebodytouseglucose

glucosetransportersmustinteractwithinsulin(braincellsexcepting)glucosetransportersSpanthecell’sexternalmembraneandbringglucosemoleculesfromoutsidethecellintothecellforuse.1.

AnotherimportantroleofinsulinEnablingthebodytouseglucoseThreedifferent,sequentialmechanismsstimulateinsulinrelease

Cephalicphase:thestimulifromfoodevokeaconditionedreleaseofinsulininanticipationofglucosearrivalinblood—mediatedbybrain

digestivephase:foodenteringthestomachandintestinescausesthemtoreleaseguthormonesstimulatethepancreastoreleaseinsulin

absorptivephase:glucodetectors(inliver)1.

AnotherimportantroleofinsulinEnablingthebodytouseglucoseThreedifferent,sequentialmechanismsstimulateinsulinreleaseTheliverandthepancreascommunicateviathenervoussystem—mediatedthebalanceLiver-glucodeterctorsVagusnerveBrainstem-NST&OtherbrainNucleusofthesolitarytractVagusnervePancreas1.

AnotherimportantroleofinsulinEnablingthebodytouseglucoseThreedifferent,sequentialmechanismsstimulateinsulinreleaseTheliverandthepancreascommunicateviathenervoussystem—mediatedthebalanceLackofinsulincausesthediseasediabetesmellitus.二.

InsulinisCrucialfortheRegulation ofBodyMetabolismAnotherimportantroleofinsulinDiabeticsMellitusDespiteItsImportance,InsulinIsNottheSoleSignalforEitherHungerorSatiety2.

DiabeticsMellitusTypeI(juvenile-onset)diabetesmellitusthepancreasstopsproducinginsulinbraincanstillmakeuseofglucosefromthediet,butbodynotHypothesis:autoimmunedisorder2.

DiabeticsMellitusTypeI(juvenile-onset)diabetesmellitusTypeII(adult-onset)diabetescausedbygraduallydecreasingsensitivitytoinsulinorgraduallydecreasingproductionofthehormone.2.

DiabeticsMellitusTypeI(juvenile-onset)diabetesmellitusTypeII(adult-onset)diabetesUntreateddiabeticseatravenouslyyetloseweight二.

InsulinisCrucialfortheRegulation ofBodyMetabolismAnotherimportantroleofinsulinDiabeticsMellitusDespiteItsImportance,InsulinIsNottheSoleSignalforEitherHungerorSatiety3.

InsulinIsNottheSoleSignalfor EitherHungerorSatietyThebrainmonitorscirculatinginsulinlevelstodecidewhenitistimetoeatandwhenitistimetostopeating

highbloodinsulinlevel—brainproducethesensationofsatietyandstopeating

lowbloodinsulinlevel—brainsignalhungrytoimpeltofindfoodandeatifinjectingalargeamountofinsulinintoanimals,andthen,whathappened?—theanimalsrespondedbyeatingalargemeal?Why?3.

InsulinIsNottheSoleSignalfor EitherHungerorSatietyThebrainmonitorscirculatinginsulinlevelstodecidewhenitistimetoeatandwhenitistimetostopeatingIscirculatingglucosesignalingsatietyandhungertothebrain?thisinformationplaysarolenormallyhowtounderstandtheuntreateddiabetics?3.

InsulinIsNottheSoleSignalfor EitherHungerorSatietyThebrainmonitorscirculatinginsulinlevelstodecidewhenitistimetoeatandwhenitistimetostopeatingIscirculatingglucosesignalingsatietyandhungertothebrain?InsulinisnottheonlysatietysignalStudiesofdiabeticratsfedahigh-fatdiet,theyeatnormalamount—fattyacids3.

InsulinIsNottheSoleSignalforEitherHungerorSatietyThebrainmonitorscirculatinginsulinlevelstodecidewhenitistimetoeatandwhenitistimetostopeatingIscirculatingglucosesignalingsatietyandhungertothebrain?InsulinisnottheonlysatietysignalSomehowthebrainintegratesinsulinandglucoselevelswithothersourcesofinformationtodecidewhethertoinitiateeatingContents:

NutrientRegulationRequirestheAnticipationofFutureNeedsInsulinisCrucialfortheRegulationofBodyMetabolismExperienceProtectsUsfromToxinsinFood

IsThereaSingleSatietyorHungerCenterintheBrainAnorexiaNervosaandBulimiaAreLife-Threatenin