CNS 2.ppt cardiovascular anatomy powerpoint f

cardiovascular short overview for medical laboratory students

1. Nervous system
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2. Introduction
Themostcomplexofthe11bodysystems.
Highlyorganizednetworkofbillionsofneuronsandmoreneuroglia.
Itaccounts2kg,about3%oftotalbodyweight
Thestructuresthatmakeupthenervoussysteminclude
Brainandcranialnerves
Spinalcord
Spinalnerves
Ganglia,entericplexuses,andsensoryreceptors
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3. Brain:whichcontainsabout100billionneurons.
Twelvepairs(rightandleft)ofcranialnerves,numberedI
throughXII,emergefromthebaseofthebrain.
Nervouscellsareneurons
Nervousarebundleofaxon,connectivetissueandblood
vessels
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4. Spinal cord
containsabout100millionneurons.
31pairsofspinalnervesemergefromthespinalcord
Gangliaaresmallmassesofnervoustissue(outsidethebrainand
spinalcord).
Sensoryreceptorisneurons(specializedcells)thatmonitor
changesintheinternalorexternalenvironment
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5. Functions of the Nervous System
Sensory input :sensory information is carried into the brain and spinal cord
Integration:to process and interpret sensory input and decide if action is
needed
Motor output: is carried out side the brain and spinal nervous
The response activates muscles or glands
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6. Nervous Tissue
Consistof2typesofcells
1.Neurons:functional,signalconductingcells
2.Neuroglia:itdoesn’tconductimpulse
Supportingcells&nutrition
Neurons:nervecells,thefunctionalandstructuralunitofthe
nervoussystem
Specializedtoconductinformationfromonepartofthebodyto
another
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Major regions of neurons
Cell body (soma) –contain nucleus other organells and metabolic
center of the cell.
Dendrites An input region -to wards the cell body
Axonconducting component , away from the cell body
A secretory (output) region (axon terminal)
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CNS
Gray matter: cell bodies and unmylenated fibers
Nuclei:clusters of cell bodies
White matter tracts:collections of myelinated fibers
PNS
Ganglia :clusters of cell bodies
Nerves: collections of myelinated fibers
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9. Structural classification of neurons
Multipolar-neurons usually have several dendrites and one axon
Bipolar-neurons have one main dendrite and one axon
They are found in the retina of the eye, in the inner ear, and in the olfactory
(to smell) area of the brain.
Unipolar-neurons have dendrites and one axon
that are fused together to form a continuous process that emerges from the
cell body
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10. Functional Classification of Neurons
Sensory: afferent neurons
Carry impulses from the sensory receptors to the CNS
Cutaneous sense organs
Most sensory neurons are Unipolar in structure.
Motor:efferent neurons
Carry impulses from the central nervous system to the muscles
or glands
Most motor neurons are multi-polarin structure.
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11. Interneurons(associationneurons)
Foundinneuralpathwaysinthecentralnervoussystem
b/ntheconnectionofsensoryandmotorneurons
Mostinterneuronsaremultipolarinstructure.
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12. Neuroglia
are supporting nerve cells
4 &2 are found in the CNS and PNS
Astrocytes
•Guide the migration of developing neurons
•Function in nutrient transfer
•Support neurons; protect neurons from harmful substances
•BBB
•
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13. Microglia:ProtectCNScellsfromdiseasebyengulfinginvading
microbes;migratetoareasofinjurednervetissuewheretheyclear
awaydebrisofdeadcells.
EpendymalCells:someareciliatedwhichfacilitatesthemovement
ofcerebrospinalfluidandcirculation
Oligodendrocytes:Producethemyelinsheathwhichprovidesthe
electricalinsulationforcertainneuronsintheCNS
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14. Neuroglia in the PNS
1.Satellite cells
•Surround clusters of neuronal cell bodies in the PNS
•Support neurons and regulate exchange of material b/n
neural cell bodies and intertistial fluid
2.Schwann cells
•Form myelin sheaths around the axon of larger nerve
fibers in the PNS.
•Vital to neuronal regeneration
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15. Organization of the Nervous System
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16. What covers and protects the CNS ?
The entire delicate CNS is protected by:
•a bony -cranial bone & vertebrae
•The menings,
•The cerebrospinal fluid (CSF)
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18. Meninges
They are three layers from outside to inside respectively
Dura mater
Arachnoid mater
Pia mater .
The dura mater: is in contact with bone
•is composed primarily of dense connective tissue.
•The cranial dura mater is a double-layered structure.
The thicker outer periosteal layer adheres tightly to the cranium,
and meningeal layer .
It extends to S2(second sacral vertebra)
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19. Arachnoidmater:isthemiddleofthethreemeninges.
Thesubarachnoidspaceislocatedbetweenthearachnoidmater
andthepiamater.
Piamater:isthedeepestattachedtothesurfacesoftheCNS
Itiscomposedofmodifiedloosefibrousconnectivetissue.
Itishighlyvascular
theligamentumdenticulatumisthelateralextensionsofthepiamater
whichattachesthespinalcordtotheduramater.
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20. Cerebrospinal fluid
•CSF is secreted by choroidal epithelial cells (ependymal cells) of the
choroid plexusesin the lateral, 3rd, and 4th ventricles
•Fills the space between
the arachnoid and pia mater
ventricles
Functions:
•Shock absorption
•Support
•Nourishment
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22. BRAIN
•a complex organ that controls
thought, memory, emotion, touch,
motor skills, vision, breathing,
temperature, hunger and every
process that regulates our body.
•Part
•Cerebrum
•Cerebellum
•brainstem
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23. Cerebrum
isthelargestportionofthebrain.
•locatedintheregionofthetelencephalon
•Itaccountsforabout80%
•isresponsibleforthehighermentalfunctionsincluding
memoryandreason
consistsof
•therighthemispheres&lefthemispheres
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25. The cerebrum consists of two layers.
cerebral cortex
•The surface layer
•is composed of gray matter( nerve cell bodies.)
•has numerous folds and grooves called convolutions.
•The elevated folds of the convolutions are the cerebral gyri
(singular, gyrus)
•the grooves are the cerebral sulci (singular, sulcus)
white matter
•Beneath the cerebral cortex
•constitutesthesecondlayer.
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26. Lobesofcerebrum
Eachcerebralhemisphereissubdividedintofivelobes
bydeepsulcicalledfissures
•Thecentralsulcus(fissureofRolando)
b/nthefrontallobeandtheparietallobe.
•Thelateralsulcus(fissureofSylvius)
b/nthefrontalandtemporallobes
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FrontalLobe
•formstheanteriorportionofeachhemisphere.
•extendsfromthecentralsulcustothefrontalpole
•concernedwithinitiatingvoluntarymotorimpulsesforthe
movementofskeletalmusclesandresponsesrelatedtomemory,
emotions,reasoning,judgment,verbalcommunications,etc
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Parietallobe
•extendsfromthecentralsulcustotheoccipitallobe
•liessuperiortothetemporallobe
•posteriortothecentralsulcus.
•function:receivesandintegratessensoryinformation
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30. Temporallobe
•lyingbelowthelateralsulcus.
•isseparatedfrombothbythelateralsulcus.
•extendsfromthelateralsulcustothecollateralsulcus.
•containsauditorycentersthatreceivesensoryfibersfrom
thecochleaoftheear
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31. Occipitallobe
•liesposteriortotheparieto-occipitalsulcusandthe
preoccipitalnotch.
•formstheposteriorportionofthecerebrum.
•liessuperiortothecerebellum.
•containsthevisualcortex
•Theprincipalfunctionoftheoccipitallobeisconcerned
withvision.
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32. Diencephalon
isthesecondsubdivisionoftheforebrainandDivide
into:
•thalamus
•hypothalamus
•theepithalamus
The3
rd
ventricleformsacavityonthemedianplane
withinthediencephalon
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34. Thalamus:
•apaired,large,avoidmassofgraymatter,constituting
nearly80%ofthediencephalon.
•Eachportionislocatedimmediatelybelowtherespective
lateralventricle.
•Itsprincipalfunctionistoactasarelaycenterforall
sensoryimpulses,exceptsmell.
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35. Hypothalamus:
Thehypothalamusperformsnumerousvitalfunctions
•hormonesecretion(pituitary)
•autonomicNScontrol
•thermoregulation(thermostat)
•food&waterintake(hunger&satiety)
•sleep&circadianrhythms
•memory(mammillarybodies)
•emotionalbehavior
anger,aggression,fear,
pleasure,sexdrive,orgasm
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36. Epithalamus:
•thedorsalportionofthediencephalonthatincludesathin
roofoverthethirdventricle.
•Thepinealglandextendsoutwardfromtheposteriorendof
theepithalamus.
•Theinsideliningoftheroofconsistsofavascular
choroidsplexuswhereCSFisproduced.
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37. Pituitarygland(hypophysis)
•issupportedbythesellaturcicaofthesphenoidbone
•positionedontheinferioraspectofthediencephalonand
isattachedtothehypothalamusbyastalk-likestructure
calledtheinfundibulum.
•Thepituitaryglandisdividedinto
•anteriorportion(adenohypophysis)
•posteriorportion(theneurohypophysis)
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38. Thebrainstem
•Thebrainstemcontainsnucleiforautonomicfunctions
ofthebodyandtheirconnectingtracts.
•Itistheportionofthebrainthatattachestothespinal
cordit:
•Includes:
themidbrain
ponsandmedullaoblongata
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40. Pons:b/nthemidbrainandthemedullaoblongata.
ithastworespiratorycentersoftheponsarecalledtheapneustic
andthepneumotaxicareas.
Medullaoblongata:functionasautonomiccentersforcontrolling
vitalvisceralfunctionsinclude
Cardiaccenter-adjustsrate&forceofheartbeat
Vasomotorcenter-adjustsbloodvesseldiameter
Respiratorycenters-controlrate&depthofbreathing
Reflexcenters-forcoughing,sneezing,gagging,swallowing,
vomiting,salivation,sweating,movementsoftongue&head
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41. Cerebellum: is the second lager structure in the brain.
occupies the inferior and posterior aspect of the cranial cavity.
attached to the brain stem by three paired bundles of nerve fibers
called cerebellar peduncles
Function: Balance
coordinating skeletal muscle contractions by recruiting precise motor units
within muscles.
Impulses for voluntary muscular movement originate in the cerebral cortex
and are coordinated by the cerebellum
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42. Spinalcord
extendsthroughthevertebralcanalandsurroundedbythree
meninges
providesameansofneuralcommunicationtoandfromthebrain
throughtractsofwhitematter.
Theseare:
•Ascendingtracts
•Descendingtracts
servesasacenterforspinalreflexes
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43. Location
•inadults,fromtheforamenmagnumtothelowerborderofthe
firstlumbarvertebraor(L2)
•innewborns,itextendstothethirdlumbar(L3)vertebra.
•continuouswiththemedullaoblongataatthespinomedullary
junction.
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45. InternalMorphology
thespinalcordconsistsofcentralgraymatterand
peripheralwhitematter.
A.Graymatter
•unmylinated
•isbutterfly-orH-shapedinaconfigurationthatvaries
accordingtospinalcordlevel.
•isdividedintothreehornsorcellcolumnsoneachside
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47. 1.Dorsal/ posterior horn
•receives and processes sensoryinput
2. Lateral horn
•receives viscerosensoryinput.
•is found between thedorsaland ventral horns.
3. Ventral/anterior horn
•contains predominately motor nuclei.
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49. Whitematter:
Dividedintoascendinganddescendingpathways.
•AscendingspinalTracts
Representfunctionalpathwaysthatconveysensory
informationfromsomaorvisceratohigherlevelsofthe
neuralaxis.
•DescendingspinalTracts:areconcernedwithsomatic
andvisceralmotoractivities.
•Itismylinated,withmyelinsheath
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50. PNS
Somaticnervoussystem
Sensoryneurons-conveyinformationfromsomaticreceptorsand
specialsensestoCNS
Motorneurons–conductimpulsesfromCNStoskeletalmuscle
only-voluntary
TheAutonomicNervousSystem(ANS).
Sensoryneurons-conveyinformationfromautonomicsensory
receptors,locatedprimarilyinvisceralorganstoCNS
Motorneurons-conductimpulsefromCNStosmoothmuscle,
cardiacmuscleandglands
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51. Theperipheralnervoussystem.
•isthatportionofthenervoussystemoutsidetheCNS.
•ThePNSfunctionstoconveyimpulsestoandfromthebrainor
spinalcord.
•ThenervesofthePNSareclassifiedas
•cranialnerves(I-XII)pairsand
spinalnerve(31)pairs
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52. Cranial nerves: 12pairs of cranial nerves
•The cranial nerves are designated by roman numerals
IOlfactorynerve–sensoryforsmell
IIOpticnerve–sensoryforvision
IIIOculomotornerve–motorfiberstoeyemuscles
IVTrochlear–motorfibertoeyemuscles
VTrigeminalnerve–sensoryfortheface;motorfiberstochewing
muscles
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53. VIAbducensnerve–motorfiberstoeyemuscles
VIIFacialnerve–sensoryfortaste;motorfiberstotheface
VIIIVestibulocochlearnerve–sensoryforbalanceandhearing
IXGlossopharyngealnerve–sensoryfortaste;motorfiberstothe
pharynx
XVagusnerves–sensoryandmotorfibersforpharynx,larynx,and
viscera
XIAccessorynerve–motorfiberstoneckandupperback
XIIHypoglossalnerve–motorfiberstotongue
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Summary of the cranial nerves
No Nerve Type Function
1 Olfactory Sensory Smell
2 Optic Sensory Vision
3 Oculomotor Motor To all muscles of the eye except two: (superior
oblique and lateral rectus)
4 Trochlear Motor To one eye muscle (superior oblique)
5 Trigeminal
Ophtalmic
Maxillary
Mandibular
Mixed: mainly, sensory; small
motor part
-Sensory to mouth, face and
anterior ½ of scalp
-Motor to muscles of mastication.
6 Abducent Motor To one eye muscle (lateral rectus)
7 Facial Mixed: motor, sensory, and
parasympathetic
-Motor to muscles of the face
-Parasympathetic to certain glands in the bead.
-Sensory: taste to anterior 2/3
rd
of tongue.
8 Auditory
(stato-acoustic)
Sensory (a)Hearing (cochlear part)
(b)Equilibrium (vestibular part)
9 Glossopharyng
eal
Mixed: motor, sensory,
and
parasympathetic
-Sensory for pharynx and tongue
-Motor to one muscle of pharynx
(stylopharyngeus)
-Parasympathetic to the parotid gland.
10Vagus
(including
cranial
accessory)
Mixed: motor, sensory
and
parasympathetic
-Motor to the muscles of the pharynx (except
stylopharyngeus), larynx and palate
-Parasympathetic and sensory to the structures
in the thorax and abdomen.
11Spinal
Accessory
Motor To 2 important muscles of the neck:
sternocleidomastoid and trapezius.
12Hypoglossal Motor To all muscles of the tongue (except
palatoglossus)
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56. Spinalnerves
31pairs–containthousandsofnervefibers
Connecttothespinalcord
Namedforpointoftissuefromthespinalcord
•8pairsofcervicalnerves(C
1-C
8)
•12pairsofthoracicnerves(T
1-T
12)
•5pairsoflumbarnerves(L
1-L
5)
•5pairsofsacralnerves(S
1-S
5)
•1pairofcoccygealnerves(Co
1)
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57. Components and branches of SN
•The SN is formed by the union of dorsal and ventral roots
resulting in a mixed nerve.
•Dorsal root
Cell bodies –located in the dorsal root ganglion
conveys sensory input from the body
•Ventral root
convey motoroutput to visceral and somatic motor
neurons.
joins the dorsal roots to form the spinal nerve
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58. Nerve plexuses
•Except in the thoracic nerves T2-T12, the anterior rami of
the spinal nerves combine and then split again as networks
of nerves referred to asplexuses.
•There are four plexuses:
the cervical
the brachial
the lumbar
sacral and
small coccygeal plexus
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Cervicalplexus(8pairs)
•formedbytheanteriorramiofthenervesC1-C4andaportion
ofC5.
•Branchesofthisinnervatetheskinandmusclesoftheneck,
andportionsoftheheadandupperpartoftheshoulders.
E.g.FibersfromC3,C4,andC5unitetoformthephrenicnerve
(C3-C5)whichinnervatesthediaphragmtherebycausingitto
contractduringinspiration
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Brachial plexus
•It’s formed by the anterior rami of the nerves C5 –C8 and T1
Fivemajornerves
•axillary-deltoid,teresminor
•radial-posteriorcompartmentofthearm
•musculocutaneus-anteriorcompartmentsofthearm
•ulnar-innervatesmusclesofanteriormedialcompartementsofthe
arm
•mediannerves-anteriorcompartmentsofthearmandsome
portionofthehand
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Lumbar plexus
•It’s formed by the anterior rami of spinal nerves (L1 -L4)
•Branches from this innervate structures of
•the lower part of abdomen
•anterior and medial potions of the lower limb.
E.g. femoral nerve innervates the anterior muscles of the thigh
•obturator nerve innervates the medial adductor muscles of the
thigh
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Pudendal , gluteal, sciatic nerves are forms the sacral plexus
•The sciatic nerve:is the largest branch of the sacral plexus and is the
largest nerve in the body.
It’s composed of two nerves: tibial and common fibular nerves.
•Tibial nerve
innervates most of the posterior thigh and leg muscles and
many of the plantar muscles.
•Common fibular nerve
innervates the anterior and lateral muscles of the leg and foot
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