10 L Nervous System Physiology.pdf…………….

The only thing that matters to me right is the fact I have to go back and forth between my two jobs to make it happen for the first two jobs and I don’t have time for it and I’m just going back and doing my own business so that makes sense to you guys have fun with it I love it and I’m so excited about that and I’m excited to be working on my new business so I’m going back and I will see what happens and then I’ll be back and hopefully I’ll get a little more work in and I can do it but I’m just excited and excited and I’m not sure what I’m going

1. 1
Nervous System
Physiology
Class notes by Dr. Hira Hameed

2. •Itisthechiefcontrolandcoordinatingsystemof
thebody
•Itadjustthebodytoitssurroundingandregulates
allbodyactivitiesbothVoluntaryandInvoluntary
•Thebasicstructuralandfunctionalunitofthe
nervoussystemisnervecellwhichisalsocalled
Neuron
•Informationprocessinginthenervoussystems
takesplacethroughexchangeofnerveimpulses
(ActionPotentials)
•MaintainsHomeostasisbythreemainfunctions
–Sensoryfunction
–Integrativefunction
–Motorfunction
2
NERVOUS SYSTEM
Class notes by Dr. Hira Hameed

3. ORGANIZATION OF NERVOUS SYSTEM
3

4. CENTRAL NERVOUS SYSTEM -CNS
4
Integratesandcorrelatesincomingsensory
information
Sourceofthoughts,emotionsandmemories
MostmotorsignalsoriginateinCNS
Consistsof…
Brain
SpinalCord
Class notes by Dr. Hira Hameed

5. NervefibersthatcarryinformationbetweenCNS
andotherpartsofbodyatperiphery.
I.AfferentDivision(Sensory)
–carryinformationtoCNS
II.EfferentDivision(Motor)
–whichcarryinformationfromCNSto
muscleandglands.
5
PERIPHERAL NERVOUS SYSTEM -PNS
Class notes by Dr. Hira Hameed

6. PERIPHERAL NERVOUS SYSTEM -PNS
6
Efferent(Motor)divisionofPNSfurtherdivideinto
SomaticNervousSystem
itisunderourvoluntarycontrolE.g.Nerve
fibersofmotorneuronthatsupplyskeletal
muscle.
AutonomicNervousSystem
itisnotunderourcontrol(involuntary)and
suppliessmoothmuscleandglands.
EntericNervousSystem
LocalnetworkofnervesintheGITcontrolling
thesecretoryandmotoractivitiesofGITand
underinfluenceofANS
Class notes by Dr. Hira Hameed

7. PERIPHERAL NERVOUS SYSTEM -PNS
7
AutonomicNervousSystem(ANS)
•ANSsuppliescardiacmuscle,smooth
muscle,glands.
•ANSisdividedinto
•Sympathetic
•Parasympathetic
Class notes by Dr. Hira Hameed

8. PERIPHERAL NERVOUS SYSTEM -PNS
8
•Neuronsinperipheralnervoussystemtransmit
signalsbetweentheReceptors&CNSorCNS
andEffectorsinthebody.
•InPeripheralNervousSystem,thereare…
•12pairsofCranialNerves.
•31pairsofSpinalNerve.
•Originsofthe31pairofSpinalnerve…
•Cervical(8pairs)
•Thoracic(12pairs)
•Lumbar(5pairs)
•Sacral(5pairs)and
•Coccygeal(1pair)Class notes by Dr. Hira Hameed

9. 9
SPINAL
NERVES
Class notes by Dr. Hira Hameed

10. PERIPHERAL NERVOUS SYSTEM -PNS
10

11. 11
CRANIAL
NERVES
Class notes by Dr. Hira Hameed

12. NEURON
•Structuralandfunctionalunitofthenervoussystem
•Thehumannervoussystemcontainabout10
12
neurons
•Mostneuronsconsistsoffollowingpart
–CellbodyorSoma
–Axonornervefiber
–Dendrite
12Class notes by Dr. Hira Hameed

13. FUNCTIONAL CLASSES OF NEURONS
ThereareTHREEfunctional
typesofNeurons
1.AfferentNeurons
–CarryinformationtoCNS.
2.EfferentNeurons
–Carryinformationawayfrom
CNS(totheperiphery).
3.Interneurons
–Theyforminteractivenetwork
betweenneuron.
13Class notes by Dr. Hira Hameed

14. AFFERENT NEURONS
•AfferentNeuron has
sensoryRECEPTORS ,
thatgeneratesaction
potentialinresponsetoa
particularstimulus.
•ThegeneratedSensory
impulseisconductedby
axontowardthespinal
cordorbrain.
•Alsocalledassensory
neurons
14Class notes by Dr. Hira Hameed

15. EFFERENT NEURONS
•Theyconductimpulses
fromthebrainandspinal
cordtoeffectorslike
MusclesandGlands.
•AlsocalledasMotor
neurons
15Class notes by Dr. Hira Hameed

16. INTERNEURONS
•Interneuronslieinbetween
theafferentandefferent
neuronsintheCNS.
•About99%ofallneuronsare
Interneurons.
•Importantinintegrating
responses toperipheral
information.
•Interconnectionsbetween
interneuronsareresponsible
forvariousphenomena
associatedwiththeconceptof
‘Mind’suchasThoughts,
Emotions,Creativity,Intellect,
MemoryandMotivation
16Class notes by Dr. Hira Hameed

17. NEUROGLIAL CELLS
•Glialcellsare
connectivetissue
ofCNS.
•Glialcellsareof
FOURtypes.
1.Astrocytes
2.Oligodendrocytes
3.Microglia
4.Ependymal Cells
17
•Glialcellssupporttheinterneuronsphysically,metabolically,
andfunctionally.
•Theydonotconductnerveimpulses.
Class notes by Dr. Hira Hameed

18. FUNCTIONS OF GLIAL CELLS
1.Astrocytes
•Functions
1.Physicalsupporttoneurons
2.Helptransfernutrientstoneurons
3.Takeupanddegradereleasedneurotransmitter
4.Enhancesynapseformation&↑Synaptictransmission
5.MaintainnormalBrainECFionconcentration
6.Formationofblood–brain–barrier
7.Repairofbraininjuries&formationofneuralscartissue
2.Oligodendrocytes
•Functions
1.FormsmyelinsheathintheCNS.
18Class notes by Dr. Hira Hameed

19. FUNCTIONS OF GLIAL CELLS
3.Microglia
•Functions
1.Phagocytosis[defensecellsofCNS]
2.Releasenervegrowthfactor
4.EpendymalCells
•Functions
1.Lineinternalcavitiesofbrainandspinalcord
2.FormationofCerebrospinalfluid[CSF].
3.WorkasNeuralStemCell–toformnew
neuronsandglialcells
19Class notes by Dr. Hira Hameed

20. Protection of Brain
20Class notes by Dr. Hira Hameed

21. Protection Of Brain
As CNS is very delicate, it
is protected by –
Skull bone and Vertebral
column
Meninges
cover brain and spinal cord.
Meninges lie between bony
covering [outside] and
nervous tissue [inside].
Meninges are Durameter,
Arachnoid and Piameter.
CSF -Cerebro Spinal
Fluid is present in
subarachnoid space.
CSF works as cushion.
Blood -brain barrier –it
selectively allows the
materials to pass to
brain.
21Class notes by Dr. Hira Hameed

22. Cerebro Spinal Fluid -CSF
•It surrounds brain and spinal cord.
•It is present in subarachnoid space.
•It is formed by choroid plexuses [capillaries in the
piameter] of ventricles in the brain.
•Volume of CSF is about 125 –150 ml.
Clinical Note:
Hydrocephalus [water in the brain].
•Occurs if CSF accumulates more, due to the block in its
circulation or reabsorption.
•If hydrocephalus is untreated, increased CSF pressure
can lead to brain damage and mental retardation.
•Treatment –surgically shunting the excess CSF to veins
elsewhere in the body.
22Class notes by Dr. Hira Hameed

23. Brain Metabolism
•Brainconstitutesonly2%ofBodyweightbutreceives
15%ofbloodpumpedbytheheart.
•Undernormalrestingconditionsthebrainuses20%of
theO
2and50%oftheGlucoseconsumedinthebody.
•BrainfunctiondependsoncontinuoussupplyofOxygen
&Glucoseasbraincannotresorttoanaerobic
metabolismlikeothertissuesanditusesonlyglucosefor
energyproductionbutcannotstoreit.
•Braindamageresultsifthereis
-NoO2supplyfor4to5mins
or
-Noglucosesupplyfor10to15mins.
23Class notes by Dr. Hira Hameed

24. Central Nervous System
•CNShasanestimated10
12
neuronswhichare
assembledintocomplexnetwork
•Functions:
–Subconsciouslyregulateinternalenvironment
–Perceptionofownbodyandsurroundingenvironment
–Reflexresponsestoexternalenvironmentchanges&
stimuli
–Voluntarilycontrolmovements
–ExperienceEmotions
–HigherCognitiveprocesseslikethoughtandmemory
24Class notes by Dr. Hira Hameed

25. Central Nervous System
Class notes by Dr. Hira Hameed 25

26. CEREBRUM
•Cerebrumconstitutes80%of
totalbrainweight.
•Outerlayer,i.e.cerebralcortex
ofcerebrumishighlyconvoluted.
•Ithasgyri[ridges]andsulci
[depression].
•GRAYMatteristheCerebral
cortex,whichconsistsofcell
bodiesofneuronandtheir
dendrites,aswellasconnective
tissueglialcells.
•WHITEMatteristhemyelinated
nervefibers(Axons).Itswhite
appearanceisduetoMyelin
sheath.
26Class notes by Dr. Hira Hameed

27. Basal Nuclei
•Thesearemassesofgraymatterlocateddeep
withinthecerebralwhitematter
•Functions:
–Co-ordinationofmovements
–Muscletoneregulation
–Posturemaintenance
27Class notes by Dr. Hira Hameed

28. Diencephalon
•Diencephalon is present in the interior of cerebrum.
•It has 2 components:
-Thalamus
-Hypothalamus
Thalamus
•All sensory information passes.
•Crude awareness of sensation.
Hypothalamus
•Regulates body temperature, has thirst and food intake
center, regulates autonomic nervous system.
28Class notes by Dr. Hira Hameed

29. Brain Stem
•BrainStem[MidBrain,Pons,Medulla].
•BrainStemiscontinuousbelowwithspinalcord.
Functions:
–Majorityofcranialnervesoriginatefrombrainstem.
–ControlCenterforcardiovascular,respiratorysystem.
–Regulationofposturalreflexes.
–Roleinsleep–wakecycle.
29Class notes by Dr. Hira Hameed

30. Cerebellum
•Cerebellum is attached at the back portion of
brain stem.
Functions:
–Balance of body.
–Muscle tone.
–Co-ordination and planning of skilled movements e.g. dance.
30Class notes by Dr. Hira Hameed