Histology of the Nervous System Nervous Tissue Histology of the Nervous System Nervous Tissue Won...

Histology of the Nervous System

Nervous Tissue

Histology of the Nervous System

Nervous Tissue

Won Taek Lee, M.D., Ph.D.

Deptartment of Anatomy

Yonsei Univ. College of Medicine

Won Taek Lee, M.D., Ph.D.

Deptartment of Anatomy

Yonsei Univ. College of Medicine

Nervous TissueNervous TissueNervous TissueNervous Tissue

Cellular ElementsCellular Elements

ŸŸ Neuron (Nerve Cell)Neuron (Nerve Cell)

ŸŸ Neuroglial Cells Neuroglial Cells central neurgliacentral neurglia

astrocyte, oligodendrocyte, microglia andastrocyte, oligodendrocyte, microglia and ependymal cellependymal cell

peripheral neurogliaperipheral neuroglia Schwann cell Schwann cell in nerve and gaglionin nerve and gaglion satellite (capsular) cell satellite (capsular) cell in ganglionin ganglion

Intercellular SubstanceIntercellular Substance: extremly scarse: extremly scarse

NeuronNeuronNeuronNeuron

Neuronal MorphologyNeuronal Morphology

Neuronal Cell Body (Soma)Neuronal Cell Body (Soma)

ŸŸ Nucleus Nucleus ŸŸ PerikaryonPerikaryon

Neuronal ProcessesNeuronal Processes

ŸŸ AxonAxon ŸŸ DendritesDendrites

cf. Diversity of Neuronal Size and Morphologycf. Diversity of Neuronal Size and Morphology

Diversity ofDiversity of

NeuronalNeuronal

MorphologyMorphology

1. nucleus1. nucleus

2. perikaryon 2. perikaryon

3. cell body3. cell body

4. axon4. axon

5. dendrite5. dendrite

6. Nissl body6. Nissl body

7. axon hillock7. axon hillock

8. myelin sheath8. myelin sheath

9. oligodendrocyte9. oligodendrocyte

10. Schwann cell10. Schwann cell

11. skeletal muscle cell11. skeletal muscle cell

12. neuromuscular junction12. neuromuscular junction

Morphology of

Typical Motor Neuron

Morphology of

Typical Motor Neuron

NeuronNeuronNeuronNeuron

Neuronal FunctionNeuronal Function

CommunicationCommunication

Receptor - Neuron - Effector Receptor - Neuron - Effector - - Excitatability (Irritability)Excitatability (Irritability) - - ConductivityConductivity through membrane through membrane in intraneuronal conductionin intraneuronal conduction

via via synapsesynapse in in interneuronal conductioninterneuronal conduction neurotransmittersneurotransmitters

Neuronal Cell Body (Soma)Neuronal Cell Body (Soma)Neuronal Cell Body (Soma)Neuronal Cell Body (Soma)

NUCLEUSNUCLEUS

ŸŸ Chromatin Pattern: Chromatin Pattern: EuchromaticEuchromatic euchromatin >>> heterochromatineuchromatin >>> heterochromatin

active active mRNAmRNA transcription transcription

cf. Barr bodycf. Barr body (facultative heterochromatin)(facultative heterochromatin)

inactive inactive X chromosomeX chromosome in female in female

ŸŸ Conspicuous NucleolusConspicuous Nucleolus NOR (nucleolar organizing region)NOR (nucleolar organizing region)

activeactive rRNArRNA transcription -- ribosometranscription -- ribosome

NB: neuronal cell bodyNB: neuronal cell body NS: Nissl substanceNS: Nissl substance

NL: nucleolusNL: nucleolus BB: Barr bodyBB: Barr body


Cytoplasmic OrganellesCytoplasmic Organelles

ŸŸ Nissl substance: Nissl substance: rERrER abundant, parallally arranged rER cisternaabundant, parallally arranged rER cisterna

active site of active site of protein (polypeptide)protein (polypeptide) synthesis synthesis

- - transport vesicletransport vesicle

ŸŸ Golgi complexGolgi complex complex of perinuclear Golgi substancecomplex of perinuclear Golgi substance glycosylation, sulfation & phosphorylationglycosylation, sulfation & phosphorylation

packing and condensation protein to transportpacking and condensation protein to transport


Protein Synthesizing AssemblyProtein Synthesizing Assembly

ŸŸ Euchromatic NucleusEuchromatic Nucleus ------- mRNA transcription------- mRNA transcription

ŸŸ Prominent NucleolusProminent Nucleolus ------- rRNA (ribosome) synthesis------- rRNA (ribosome) synthesis

ŸŸ Nissl substance:Nissl substance: rERrER ------- polypeptide chain------- polypeptide chain

ŸŸ Golgi complexGolgi complex ----- ----- destined to transportdestined to transport

-- no protein synthesizing assembly in axonno protein synthesizing assembly in axon - neurotransmitters, enzymes, membrane proteins- neurotransmitters, enzymes, membrane proteins - transport via axonal (axoplasmic) transporttransport via axonal (axoplasmic) transport


Other Cytoplasmic OrganellesOther Cytoplasmic Organelles

ŸŸ Mitochondria Mitochondria - - energy source for energy source for ion exchangeion exchange (Na (Na++-K-K++ exchange pump) exchange pump) and and axonal transportaxonal transport

ŸŸ LysosomeLysosome - hydrolytic enzymes --- waste products- hydrolytic enzymes --- waste products - lysosomal storage disease (mental retardation, seizure)- lysosomal storage disease (mental retardation, seizure)

Pigment GranulesPigment Granules

Lipofuscin granuleLipofuscin granule, , Melanin granuleMelanin granule


CytoskeletonCytoskeleton

ŸŸ Neurofilament: Intermediate Filament Neurofilament: Intermediate Filament - supporting- supporting

- neurofibril -------- neurofibril ------- reduced silver stainingreduced silver staining

Fink-Heimer methodFink-Heimer method

ŸŸ MicrotubuleMicrotubule - tubulin- tubulin - fast anterograde axonal transport and- fast anterograde axonal transport and retrograde axonal transportretrograde axonal transport

cf. microfilament:cf. microfilament: actin, postsynaptic membraneactin, postsynaptic membrane

CytoskeletonCytoskeleton

NeurofilamentNeurofilament

MicrotubuleMicrotubule

Neurofibril - Neurofibril - neurofilamentneurofilament

SYNAPSESYNAPSESYNAPSESYNAPSE

ŸŸ Presynaptic Portion: Synaptic Button Presynaptic Portion: Synaptic Button - synaptic vesicle- synaptic vesicle

- mitochondria- mitochondria - presynaptic membrane: tubulin- presynaptic membrane: tubulin

ŸŸ Synaptic Cleft Synaptic Cleft - 20-30 nm- 20-30 nm

ŸŸ Postsynaptic PortionPostsynaptic Portion - postsynaptic membrane: actin, fodrin, spectrin- postsynaptic membrane: actin, fodrin, spectrin

- mitochondria- mitochondria

SYNAPSESYNAPSESYNAPSESYNAPSE

SYNAPSESYNAPSE

Components of Axonal (Axoplasmic) TransportComponents of Axonal (Axoplasmic) Transport

Components Velocity (mm/day) Transporting SubstancesComponents Velocity (mm/day) Transporting Substances

Anterograde Axonal TransportAnterograde Axonal Transport Fast Transport Fast Transport 200-400200-400 synaptic vesicle, enzymes neurotransmitters Mitochondrial Transport 50-10050-100 mitochondria

Slow TransportSlow Transport

Slow Components a (SCa) 0.1 - 1.00.1 - 1.0 tubulin, neurofilament protein Slow Comnponent b (SCb) 2 - 62 - 6 actin, clathrine, calmodulins spectrin, cytoplasmic enzymes Retrograde Axonal Transport Retrograde Axonal Transport 100-200100-200 prelysosomal vesicles, recycled proteins, HRP, WGA neurotrophic viruses

Axonal (Axoplasmic) TransportAxonal (Axoplasmic) TransportAxonal (Axoplasmic) TransportAxonal (Axoplasmic) Transport

Mechanism ofMechanism of Axonal Axonal TransportTransport

FastFast AnterogradeAnterograde Axonal transportAxonal transport

andand

RetrogradeRetrograde Axonal transportAxonal transport

Mechanism ofMechanism of Axonal Axonal TransportTransport

FastFast AnterogradeAnterograde Axonal transportAxonal transport

andand

RetrogradeRetrograde Axonal transportAxonal transport

Retrograde Tracing MethodsRetrograde Tracing Methods

1. Nissl Reaction1. Nissl Reaction

methylene blue, toluidine blue,methylene blue, toluidine blue,

thionin, cresyl violetthionin, cresyl violet

2. Retrograde Tracer2. Retrograde Tracer

Horseradish Peroxidase (HRP)Horseradish Peroxidase (HRP)

Wheat-germ Agglutinin (WGA) Wheat-germ Agglutinin (WGA)

Fluorescence TracerFluorescence Tracer

- Lucifer Yellow, Fast Blue, Nuclear Yellow- Lucifer Yellow, Fast Blue, Nuclear Yellow

Viruses and ToxoidsViruses and Toxoids

Tract Tracing Methods (I)Tract Tracing Methods (I)Tract Tracing Methods (I)Tract Tracing Methods (I)

Anterograde Tracing MethodsAnterograde Tracing Methods

1. Marchi Method1. Marchi Method

OsO4 after tract of nerve lesionOsO4 after tract of nerve lesion

2. Nauta Method - Fink Heimer method2. Nauta Method - Fink Heimer method

Reduced Silver Method after tract lesionReduced Silver Method after tract lesion

3. Autoradiograhy with Radiolabelled Amino Acid3. Autoradiograhy with Radiolabelled Amino Acid

Tritiated Glycine Tritiated Glycine

4. Anterograde Tracer4. Anterograde Tracer

Phageolus Vulgaris Leucoagglutinin (PHA-L)Phageolus Vulgaris Leucoagglutinin (PHA-L)

Tract Tracing Methods (II)Tract Tracing Methods (II)Tract Tracing Methods (II)Tract Tracing Methods (II)

Degeneration and RegenerationDegeneration and Regenerationof Nervous Systemof Nervous System

Degeneration and RegenerationDegeneration and Regenerationof Nervous Systemof Nervous System

1. Wallerian Degeneration1. Wallerian Degeneration - changes distal to the injury site- changes distal to the injury site - myelin breakdown- myelin breakdown - von B- von Büüngner’s band - Schwann cellngner’s band - Schwann cell - neuroma formation- neuroma formation

2. Axon Reaction (Chromatolysis, 2. Axon Reaction (Chromatolysis, Nissl Reaction)Nissl Reaction) - displacement of nucleus- displacement of nucleus - chromatolysis- chromatolysis - regenerative processes- regenerative processes

1. injury site

2. Nissl substance

3. axon

4. proximal portion

5. axon sprout

6. Schwann cell

7. fat droplet

8. macrophage

9. Büngner's band

1. injury site

2. Nissl substance

3. axon

4. proximal portion

5. axon sprout

6. Schwann cell

7. fat droplet

8. macrophage

9. Büngner's band

Classification of NeuronsClassification of NeuronsClassification of NeuronsClassification of Neurons

(1) by the Number of Processes(1) by the Number of Processes 1. unipolar neuron1. unipolar neuron 2. pseudounipolar neuron2. pseudounipolar neuron 3. bipolar neuron3. bipolar neuron 4. multipolar neuron4. multipolar neuron

(2) by the Length of Axon(2) by the Length of Axon 1. Golgi type I neuron1. Golgi type I neuron 2. Golgi type II neuron2. Golgi type II neuron

(3) by the Morphology of Dendrites(3) by the Morphology of Dendrites (Topognostic Value)(Topognostic Value) 1. isodendritic neuron1. isodendritic neuron 2. allodendritic neuron2. allodendritic neuron 3. idiodendritic neuron3. idiodendritic neuron

1. unipolar neuron 2. bipolar neuron

3. pseudounipolar neuron 4. multipolar neuron

a. axon d. dendrite

1. unipolar neuron 2. bipolar neuron

3. pseudounipolar neuron 4. multipolar neuron

a. axon d. dendrite

Neuroglia (Neuroglial Cells)Neuroglia (Neuroglial Cells)Neuroglia (Neuroglial Cells)Neuroglia (Neuroglial Cells)

Central NeurogliaCentral Neuroglia AstrocyteAstrocyte protoplasmic astrocyteprotoplasmic astrocyte fibrous astrocytefibrous astrocyte

OligodendrocyteOligodendrocyte perineuronal satellite cellperineuronal satellite cell interfascicular cellinterfascicular cell

MicrogliaMicroglia Ependymal CellEpendymal Cell

Peripheral NeurogliaPeripheral Neuroglia Schwann CellSchwann Cell

in peripheral nervein peripheral nerve

and ganglionand ganglion

Capsular (Satellite) CellCapsular (Satellite) Cell

in ganglionin ganglion

AstrocyteAstrocyte Oligodendrocyte Oligodendrocyte Microglia Microglia

Central NeurogliaCentral NeurogliaCentral NeurogliaCentral Neuroglia

AstrocyteAstrocyteAstrocyteAstrocyte

• Protoplasmic Astrocyte: Gray Matter Protoplasmic Astrocyte: Gray Matter • Fibrous Astrocyte: White MatterFibrous Astrocyte: White Matter

Cell BodyCell Body ‘‘potato’ shape nucleus, scarse pale cytopasmpotato’ shape nucleus, scarse pale cytopasm

ProcessesProcesses - - GFAP GFAP (glial fibroacidic protein):(glial fibroacidic protein): intermediate filament intermediate filament

-- Perivascular Feet Perivascular Feet (Foot Process, Vascular End-Feet)(Foot Process, Vascular End-Feet) surrounding blood vesselssurrounding blood vessels

Specialized AstrocytesSpecialized Astrocytes

- Bergmann’s gial cell, Muller cell, pituicyte- Bergmann’s gial cell, Muller cell, pituicyte

ProtoplasmicProtoplasmic Fibrous Fibrous Synaptic Synaptic

AstrocyteAstrocyte AstrocyteAstrocyte Glomerulus Glomerulus

OligodendrocyteOligodendrocyteOligodendrocyteOligodendrocyte

• Perineuronal Satellite Cell Perineuronal Satellite Cell • Interfascicular CellInterfascicular Cell

Cell BodyCell Body round, heterochromatic nucleusround, heterochromatic nucleus dark cytopasmdark cytopasm - rER, free ribosome, Golgi complex, mitochondria- rER, free ribosome, Golgi complex, mitochondria

Myelin forming cell in CNSMyelin forming cell in CNS - - Myelin SheathMyelin Sheath

Each process constitutes a Each process constitutes a internodal segmentinternodal segment

Oligodendrocyte

1. nucleus of

oligodendrocyte

2. process of

oligodendrocyte

3. myelin sheath

4. axon

Oligodendrocyte

1. nucleus of

oligodendrocyte

2. process of

oligodendrocyte

3. myelin sheath

4. axon

MicrogliaMicrogliaMicrogliaMicroglia

Cell BodyCell Body slender, indented, heterochromatic nucleusslender, indented, heterochromatic nucleus dark cytopasmdark cytopasm - prominent secondary lysosome- prominent secondary lysosome

ProcessesProcessesshort, highly branchedshort, highly branched

Macrophage (Mononuclear Phagocytic) SystemMacrophage (Mononuclear Phagocytic) SystemMesenchymal Origin - Blood MonocyteMesenchymal Origin - Blood MonocyteIncreased inIncreased in Inflammation Inflammation

Microglia

1. nucleus of

microglia

2. process of

microglia

3. lysosome

4. capillary

5. pericyte

Microglia

1. nucleus of

microglia

2. process of

microglia

3. lysosome

4. capillary

5. pericyte

Ependymal CellEpendymal CellEpendymal CellEpendymal Cell

Epithelial Cell Epithelial Cell lining ventricular surfacelining ventricular surface cilia and microvilli on luminal surfacecilia and microvilli on luminal surface simple cuboidal cell with round nucleussimple cuboidal cell with round nucleus

TanicyteTanicytebasal process, numerous in 3rd ventriclebasal process, numerous in 3rd ventriclemost ependymal cell has basal processmost ependymal cell has basal process (Chung & Lee, 1988)(Chung & Lee, 1988)

Choroid Plexus Epithelial CellsChoroid Plexus Epithelial Cellsion transporting cell: numerous mitochondriaion transporting cell: numerous mitochondria

Schwann CellSchwann CellSchwann CellSchwann Cell

Slender Cell Slender Cell with small heterochromatic nucleiwith small heterochromatic nuclei

Myelin forming cell in PNSMyelin forming cell in PNS - - Myelin Sheath: Myelin Sheath: Myelinated FiberMyelinated Fiber

A Schwann cell constitutes a internodal SegmentA Schwann cell constitutes a internodal Segment

Surround Surround Unmyelinated AxonsUnmyelinated Axons A schwann cell surround A schwann cell surround

many unmyelinated axonsmany unmyelinated axons

Schwann CellSchwann Cell

Satellite (Capsular) CellSatellite (Capsular) CellSatellite (Capsular) CellSatellite (Capsular) Cell

Squamous Cell encircles Squamous Cell encircles neuronal cell bodyneuronal cell body

in Ganglion in Ganglion

- completely encircles pseudounipolar neuron- completely encircles pseudounipolar neuron

in in spinal and cranial ganglionspinal and cranial ganglion

- neurons of autonomic ganglia were - neurons of autonomic ganglia were

less completely surrounded by satellite cellless completely surrounded by satellite cell

Myelin Sheath - MYELINMyelin Sheath - MYELIN cf. Schwann sheath, Neurilemmacf. Schwann sheath, Neurilemma

• formed by wrapped plasma membrane offormed by wrapped plasma membrane of OligodendrocyteOligodendrocyte in CNS in CNS Schwann CellSchwann Cell in PNS in PNS

• Node of RanvierNode of Ranvier - Saltatory Conduction - Saltatory Conduction evolutionary innovation in chordateevolutionary innovation in chordate - - conduction velocityconduction velocity

MyelinMyelinMyelinMyelin


Node of Ranvier - Internodal segmentNode of Ranvier - Internodal segmentSchmidt-Lantermann’s cleftSchmidt-Lantermann’s cleft


Conduction velocityConduction velocity is proportional to is proportional to

1. The Length of Internodal Segment1. The Length of Internodal Segment

2. Thickness of Myelin2. Thickness of Myelin

3. Diameter of Nerve Fiber3. Diameter of Nerve Fiber

Myelin FormationMyelin FormationMyelin FormationMyelin Formation


MyelinMyelinformationformation

Schwann cellSchwann celloligodendrocyteoligodendrocyte

MYELIN - Fusion of Plasma MembraneMYELIN - Fusion of Plasma Membrane Major Dense LineMajor Dense Line - fusion of inner leaflet - fusion of inner leaflet ---- Myelin Basic Protein (MBP)---- Myelin Basic Protein (MBP)

Intraperiod LineIntraperiod Line - fusion of outer leaflet - fusion of outer leaflet ---- Proteolipid Protein (PLP)---- Proteolipid Protein (PLP)

in oligodendrocytein oligodendrocyte ---- Protein Zero (P---- Protein Zero (P00) )

in Schwann Cellin Schwann Cell



1. trilaminar unit membrane1. trilaminar unit membrane 2. major dense line 2. major dense line

3. intraperiod line3. intraperiod line 4. Cytoplasm of Schwann cell 4. Cytoplasm of Schwann cell

Organization of Nervous SystemOrganization of Nervous SystemOrganization of Nervous SystemOrganization of Nervous System

Central Nervous SystemCentral Nervous System

Gray MatterGray Matter Nucleus and CortexNucleus and Cortex White MatterWhite Matter TractsTracts

Peripheral Nervous SystemPeripheral Nervous System

Nerve (Peripheral Nerve)Nerve (Peripheral Nerve) GanglionGanglion

Peripheral NervePeripheral NervePeripheral NervePeripheral Nerve

Nerve FiberNerve Fiber

Myelinated Nerve Fiber Myelinated Nerve Fiber Axon, Axon, Myelin sheathMyelin sheath, Schwann cell , Schwann cell Unmyelinated Nerve Fiber Unmyelinated Nerve Fiber Axon, Schwann cell Axon, Schwann cell

Connective Tissue SheathConnective Tissue Sheath

EndoneuriumEndoneurium PerineuriumPerineurium EpineuriumEpineurium

Peripheral NervePeripheral NervePeripheral NervePeripheral Nerve

Nervous SystemNervous SystemNervous SystemNervous System

• Central Nervous SystemCentral Nervous System brain, spinal cord: brain, spinal cord: nervous tissuenervous tissue meninges, choroid plexus: meninges, choroid plexus: connective tissueconnective tissue

• Peripheral Nervous SystemPeripheral Nervous System nerve, ganglion, nerve plexusnerve, ganglion, nerve plexus:: nervous tissuenervous tissue and and connective tissueconnective tissue

cf.cf. SomaticSomatic vs vs AutonomicAutonomic Nervous System Nervous System Enteric Nervous SystemEnteric Nervous System

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