ppt (5).ppt brain parts anatomy of bs mls

Brain anatomy

1. PartsoftheBrain

2. PartsoftheBrain
•Thebrainisthatpartofthecentralnervoussystemthat
liesinsidethecranialcavity.Itiscontinuouswiththespinal
cordthroughtheforamenmagnum.

9. Cerebrum
•Thecerebrumisthelargestpartofthebrainandconsists
oftwocerebralhemispheresconnectedbyamassofwhite
mattercalledthecorpuscallosum.
•Eachhemisphereextendsfromthefrontaltotheoccipital
bones;abovetheanteriorandmiddlecranialfossae;and,
posteriorly,abovethetentoriumcerebelli.

10. •Thesurfacelayerofeachhemisphereiscalledthecortexand
is composedofgraymatter.
•cortexisthrownintofolds,orgyri,separatedbyfissures,or
sulci.
•Bythismeans,thesurfaceareaofthecortexisgreatly
increased.
•Severalofthelargesulciconvenientlysubdividethesurfaceof
eachhemisphereintolobes.

13. LobesofCerebrum
•Thefrontallobeissituatedinfrontofthecentralsulcusand
abovethelateralsulcus.
•Theparietallobeissituatedbehindthecentralsulcusand
abovethelateralsulcus.
•Theoccipitallobeliesbelowtheparietooccipitalsulcus.
•Belowthelateralsulcusissituatedthetemporallobe.

19. RightsideofBrain
Structureofbrain

20. Motorarea
•Theprecentralgyrusliesimmediatelyanteriortothecentral
sulcusandisknownasthemotor area.
•Thelargemotornervecellsinthisareacontrolvoluntary
movementsontheoppositesideofthebody.
•Inthemotorarea,thebodyisrepresentedinaninverted
position,withthenervecellscontrollingthemovementsof
thefeetlocatedintheupperpartandthosecontrollingthe
movementsofthefaceandhandsinthelowerpart

26. Sensoryarea
•Thepostcentralgyrusliesimmediatelyposteriortothe
central
sulcusandisknownasthesensoryarea
•Thesmallnervecellsinthisareareceiveandinterpret
sensationsofpain,temperature,touch,andpressurefrom
theoppositesideofthebody.

28. Auditoryarea
•Thesuperiortemporalgyrusliesimmediatelybelowthelateral
sulcus
•Themiddleofthisgyrusisconcernedwiththereceptionand
interpretationofsoundandisknownastheauditoryarea.

30. Speecharea
•Broca’sarea,orthemotorspeecharea,liesjustabovethe
lateralsulcus
•Itcontrolsthemovementsemployedinspeech.
•Itisdominantinthelefthemisphereinright-handedpersons
andintherighthemisphereinleft-handedpersons.

32. Visualarea
•Thevisualareaissituatedontheposteriorpoleandmedial
aspectofthecerebralhemisphereintheregionofthe
calcarinesulcus
•Itisthereceivingareaforvisualimpressions.

35. Lateralventricle
•Thecavitypresentwithineachcerebralhemisphereiscalled
thelateralventricle.
•lateralventriclescommunicatewiththethirdventricle
throughtheinterventricular
•foramina

36. Diencephalon
•Thediencephalonisalmostcompletelyhiddenfromthe
surfaceofthebrain.
•Itconsistsofadorsalthalamusandaventralhypothalamus.
•Thethalamusisalargemassofgraymatterthatliesoneither
sideofthethirdventricle.
•Itisthegreatrelaystationontheafferentsensorypathwayto
thecerebralcortex.

37. continued
•Thehypothalamusformsthelowerpartofthelateralwall
and floorofthethirdventricle.
•Thefollowingstructuresarefoundinthefloorofthethird
ventriclefrombeforebackward:theopticchiasmathetuber
cinereumandtheinfundibulum,themammillarybodies,and
theposteriorperforatedsubstance.

44. The
Meninges
•Thebrainintheskullissurroundedbythree
protectivemembranes,ormeninges:
•Theduramater,
•Thearachnoidmater,and
•Thepiamater.

46. DuraMateroftheBrain
•Theduramaterisconventionallydescribedas twolayers:
•TheendosteallayerandthemeningeallayerTheseare
closelyunitedexceptalongcertainlines,wherethey
separatetoformvenoussinuses.
•Theendosteal layer isnothingmorethantheordinary
periosteumcoveringtheinnersurfaceoftheskullbones.

47. •Themeningeal layer istheduramaterproper.
•Itisadense,strong,fibrousmembranecoveringthebrain
andiscontinuousthroughtheforamenmagnumwiththe
duramaterofthespinalcord.
•Itprovidestubularsheathsforthecranialnervesasthelatter
passthroughtheforaminaintheskull.

50. FoldsofDuraMatter
•Thefalxcerebriisasickle-shapedfoldofduramaterthatliesin
themidlinebetweenthetwocerebralhemispheres.
•Thetentoriumcerebelliisacrescent-shapedfoldofduramater
thatroofsovertheposteriorcranialfossa.
•Thefalxcerebelliisasmall,sickle-shapedfoldofduramater
•Thediaphragmasellaeisasmallcircularfoldof
duramater

52. ArachnoidMateroftheBrain
•Thearachnoidmaterisadelicate,impermeable
membranecoveringthebrainandlyingbetweenthepia
materinternallyandtheduramaterexternally.
•Itisseparatedfromthedurabyapotentialspace,the
subduralspace,andfromthepiabythesubarachnoid
space,whichisfilledwithcerebrospinalfluid.

54. CerebrospinalFluid
•Thecerebrospinalfluidisproducedbythechoroidplexuses
withinthelateral,third,andfourthventriclesofthebrain.
•Itescapesfromtheventricularsystemofthebrainthroughthe
threeforaminaintheroofofthefourthventricleandsoenters
thesubarachnoidspace.
•Itnowcirculatesbothupwardoverthesurfacesofthecerebral
hemispheresanddownwardaroundthespinalcord.

55. •Thespinalsubarachnoidspaceextendsdown
asfarasthesecondsacralvertebra.
•Eventually,thefluidentersthebloodstreambypassinginto
thearachnoidvillianddiffusingthroughtheirwalls.
•Thecerebrospinalfluidprovidesafluid
mediuminwhichthebrainfloats.
•Thismechanismeffectivelyprotectsthebrainfromtrauma.

57. PiaMateroftheBrain
•Thepiamaterisavascularmembranethatcloselyinveststhe
brain,coveringthegyrianddescendingintothedeepest
sulci.
•Itextendsoverthecranialnervesandfuses
withtheirepineurium.
•Thecerebralarteriesenteringthesubstanceofthebrain
carryasheathofpiawiththem.