Download The Nervous System

The Nervous System
Origin of the nervous system
• neurulation
• neural induction => neural plate =>
neural folds (C4 somite)……… notogenesis
• caudal morphogenetic system
• paraxial mesoderm
• neuroporus anterior
• neuroporus posterior
Neural tube defects (NTDs)
• spina bifida
• anencephalia
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
Segmentation, morphogenesis
• => brain vesicles
=> spinal segments
• differentiation, determination, induction, apoptosis
• homeotic genes
Neural tube histogenesis
• neuroepithelium
• lamina limitans interna
• membrana limitans externa
layers (zones):
• inner - germinal (ventricular)
• intermediate - mantle
• outer - marginal
The development of the spinal cord
• epithelium => zones:
- ventricular
- intermediate
- marginal
• floor and roof plate
• sulcus limitans
• alar and basal plate
The spinal cord
• white matter
• grey matter
• positional changes of the spinal cord
The spinal cord:
N5 (HE)
N6 (gallocyanin)
The development of the brain
• prosencephalon
=> telencephalon
=> diencephalon
• mesencephalon
• rhombencephalon
=> metencephalon
=> myelencephalon
• flexura cervicalis et mesencephalica, f. pontina
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
Cerebrum
• allocortex
1. lamina zonalis (molecularis)
2. stratum pyramidale
3. lamina multiformis
Cortex cerebri:
N1 (HE)
N2 (myelin)
The development of the cerebellum
<= dorsal parts of the alar plate
structure according to the fylogenesis:
• archicerebellum
• paleocerebellum
• neocerebellum
The Cerebellum
• grey matter - cortex:
- molecular layer
- intermediate layer of the Purkyne cells
- granular layer
• white matter
- „arbor vitae“
Cerebellum:
N3 (HE)
N4 (kresyl violet)
Meninges
• dura mater
• arachnoid
• pia mater
• blood - brain barrier
Rhombencephalon - pl.chorioideus
• tela chorioidea
= thin lamel of the columnar cells of ependym
- pia mater on the surface
=> infolding in the ventricle IV - plexus
chorioideus
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
Plexus choroideus:
N7 (HE)
Peripheral nervous system
• neurofibres - endoneurium
• bundles of the fibres - perineurium
• nerves- epineurium
- afferent, efferent, mixture
• ganglia
Peripheral nerve:
N10 (HE)
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
Sensory ganglion:
N8 (HE)
Autonomic ganglion:
N9 (HE)