The cerebrum (front of brain) comprises gray matter (the cerebral cortex) and white matter at its center. The largest part of the brain, the cerebrum ...SkipNavigationImportantUpdates:COVID-19vaccinations|RecallonPhilipsRespironicsmedicaldevicesCOVID-19:Wearevaccinatingpatientsages12+.Learnmore:Vaccines,Boosters&AdditionalDoses|Testing|PatientCare|VisitorGuidelines|Coronavirus|Self-Checker|EmailAlerts PhilipsRespironicsissuedarecallforsomeCPAPandBiLevelPAPdevicesandmechanicalventilators.Learnmore.HealthHomeConditionsandDiseasesBrainAnatomyandHowtheBrainWorksShareonFacebookShareonTwitterShareonLinkedinShareonPinterestShareviaEmailPrintthisPageWhatisthebrain?Thebrainisacomplexorganthatcontrolsthought,memory,emotion,touch,motorskills,vision,breathing,temperature,hungerandeveryprocessthatregulatesourbody.Together,thebrainandspinalcordthatextendsfromitmakeupthecentralnervoussystem,orCNS.Whatisthebrainmadeof?Weighingabout3poundsintheaverageadult,thebrainisabout60%fat.Theremaining40%isacombinationofwater,protein,carbohydratesandsalts.Thebrainitselfisanotamuscle.Itcontainsbloodvesselsandnerves,includingneuronsandglialcells.Whatisthegraymatterandwhitematter?Grayandwhitematteraretwodifferentregionsofthecentralnervoussystem.Inthebrain,graymatterreferstothedarker,outerportion,whilewhitematterdescribesthelighter,innersectionunderneath.Inthespinalcord,thisorderisreversed:Thewhitematterisontheoutside,andthegraymattersitswithin.Graymatterisprimarilycomposedofneuronsomas(theroundcentralcellbodies),andwhitematterismostlymadeofaxons(thelongstemsthatconnectsneuronstogether)wrappedinmyelin(aprotectivecoating).Thedifferentcompositionofneuronpartsiswhythetwoappearasseparateshadesoncertainscans.Eachregionservesadifferentrole.Graymatterisprimarilyresponsibleforprocessingandinterpretinginformation,whilewhitemattertransmitsthatinformationtootherpartsofthenervoussystem.Howdoesthebrainwork?Thebrainsendsandreceiveschemicalandelectricalsignalsthroughoutthebody.Differentsignalscontroldifferentproc