The Nervous System

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The Nervous System
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Origin of the nervous system

• neurulation
• neural induction gt neural plate gt
• neural folds (C4 somite) notogenesis
• caudal morphogenetic system
• paraxial mesoderm
• neuroporus anterior
• neuroporus posterior

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Neural tube defects (NTDs)

• spina bifida
• anencephalia

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Neural crest
melanocytes, odontoblasts, suprarenal medulla
(chromaffin cells),
Schwann cells of peripheral axons,
oligodendrocytes,
satelitte cells of the ganglia, cells of the pia
mater and the arachnoidea, postganglionic neurons
of the ANS, sensory ganglia of the PNS
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Segmentation, morphogenesis

• gt brain vesicles
• gt spinal segments
• differentiation, determination, induction,
  apoptosis
• homeotic genes

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Neural tube histogenesis

• neuroepithelium
• lamina limitans interna
• membrana limitans externa
• layers (zones)
• inner - germinal (ventricular)
• intermediate - mantle
• outer - marginal

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The development of the spinal cord

• epithelium gt zones
• - ventricular
• - intermediate
• - marginal
• floor and roof plate
• sulcus limitans
• alar and basal plate

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The spinal cord

• white matter
• grey matter
• positional changes of the spinal cord

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The spinal cordN5 (HE)N6 (gallocyanin)
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The development of the brain

• prosencephalon
• gt telencephalon
• gt diencephalon
• mesencephalon
• rhombencephalon
• gt metencephalon
• gt myelencephalon
• flexura cervicalis et mesencephalica, f. pontina

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Cerebrum

• izocortex - laminae
• 1. zonalis - tinny multipolar neurons
• 2. granularis externa - small pyramidal cells
• 3. pyramidalis - middle-size multipolar neurons
• 4. granularis interna - small neurons,
  Martinotti cells
• 5. ganglionaris - gigantic Betz pyramids
• 6. multiformis - large polymorphic
  neurons,Martinotti cells

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Cerebrum

• allocortex
• 1. lamina zonalis (molecularis)
• 2. stratum pyramidale
• 3. lamina multiformis

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Cortex cerebriN1 (HE)N2 (myelin)
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The development of the cerebellum

• lt dorsal parts of the alar plate
• structure according to the fylogenesis
• archicerebellum
• paleocerebellum
• neocerebellum

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The Cerebellum

• grey matter - cortex
• - molecular layer
• - intermediate layer of the Purkyne cells
• - granular layer
• white matter
• - arbor vitae

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CerebellumN3 (HE)N4 (kresyl violet)
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Meninges

• dura mater
• arachnoid
• pia mater
• blood - brain barrier

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Rhombencephalon - pl.chorioideus

• tela chorioidea
• thin lamel of the columnar cells of ependym
• - pia mater on the surface
• gt infolding in the ventricle IV - plexus
  chorioideus

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Plexus choroideus

• invaginated folds of pia mater that penetrate
  the interior of the ventricles
• epithelium continual the ependym
• under the apex - intercellular connections
• fenestrated capillaries with diaphragm
• function

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Plexus choroideusN7 (HE)
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Peripheral nervous system

• neurofibres - endoneurium
• bundles of the fibres - perineurium
• nerves- epineurium
• - afferent, efferent, mixture
• ganglia

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Peripheral nerve N10 (HE)
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PNS - ganglia

• intramural
• - GIT etc., parasympathetic system
• craniospinal (sensory,of the dorsal spinal roots)
• - pseudounipolar neurons
• - bipolar only in the ganglion n. VIII
• - periphery neurocytes
• - central nerve fibres
• autonomic
  - multipolar,
  efferent neurons, regular arranged
  - incomplete layer of the satellite
  cells

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Sensory ganglion N8 (HE)Autonomic ganglion
N9 (HE)