1. Microscopic structure – practice 2013
89. Nerve tissue
Microscopic structure – practice 2013

2. Nerve tissue - morphology
cells : 1.neurons and 2.glial cells
extracellular material is extremely reduced replaced by glial branched process
neuropil – high amount of synapses, dendrite´s arborisation, non-myelinated axons
extensive vasculature with variable amount of connective tissue both in CNS and PNS
blood-brain barrier in CNS

3. Tissue microscopic structure: cells with processes – integrated communicating network
neuron theory – contact junctions among neurons

4. NEURON is structural and functional unit of nerve tissue
N3 – cerebellum,HE
NEURON is structural and functional unit of nerve tissue

5. Nerve tissue microstructure (example 2 – brain )
Glial c.
Neuron

7. Perikaryon (soma, cell body) receptor region, integration, trophic centre
nucleus
large, lightly basophilic, with dispersed chromatin, prominent nucleolus
RER
abundant → substance of Nissl - tigroid
Golgi apparatus
only in perikaryon!
cytoskeleton (neurofilaments)
mitochondria
inclusions
lipofuscin, melanin

8. Cytoskeleton Microtubules
axonal transport (anterograde, retrograde, microtubule-associated motor proteins used ATP – dynein, kinesin)
shape regulation
Neurofilaments (intermediate filaments in neurons)
resistance against deformations
regulatory process
Microfilaments (aktin)

9. Dendrites receptor region
principal recieving site
arborisation (branching) increases receptive area of the cell
( contacts and more)
dendritic spines (site of synapse - postsynaptic membrane, actin microfilaments
neurofilaments (NF-L, NF-M, NF-H), other cytoskeleton units, proteosynthetic apparatus except GA
always non- myelinated

10. Axon conductive region
transmit stimuli in the form of action potential to other neuron or effector cell
1 neuron has 1 axon
metabolically dependent on perikaryon
Golgi type I neurons – motor neurons of CNS with long axon (up to 1 meter) terminate on skeletal muscle
Golgi type II neurons – short axons
axon hillock, initial segment – site of action potential generation
axonal transport transport vesicles, mitochondria , proteins…by anterograde x growth factor, viruses..by retrograde

11. Synapse effector region, unidirectional transmission of nerve impulse
presynaptic (axonal) terminal + postsynaptic (dendritic, somatic, axonal) membrane
site of chemical message transmission in response to action potential
presynaptic : synaptic vesicles with neurotransmitters, microtubules+kinesin, mitochondria
synaptic cleft 40nm
postsynaptic membrane of effector cell:
nerve cell
muscle cell
secretory cell
axodendritic,axosomatic,axoaxonal, „en passant“

12. Neuroglia supporting sell population for neurons
provide neurons with structural support and maintain local condition for neuronal function
forming 50% volume of CNS
10 x more abundant than neurons
histological staining
impregnation by Ag, Au salts, histochemical technics

13. Glia - types in CNS 1. macroglia astrocytes oligodendrocytes
ependymal cells
2. Microglia
in PNS
Schwann cells
Satelite cells

15. Neurons and neuroglia are cells with processes

16. B45 Brain/Cerebrum LFB, luxol fast blue, myelin staining

17. B44 Brain/ Cerebrum (HE)

18. Neuron, neuroglia, blood vessel

19. N3 - cerebellum HE
Purkyňova buňka
Granulární neuron

20. B46 Small brain, cerebellum HE

21. Spinal cord / cross section - B48

22. B48 Spinal cord HE

23. Ependym epitheloid arrangement of ependymal cells
neural tube neuropithelium remnant

24. B49 Autonomic ganglion

25. B50 Peripheral nerve

26. Peripheral nerve

27. Myelinated nerve fibres
Eg 13 - Myelinizovaný axon

28. Myelinated nerve fibres
in PNS: axons are invaginated into cytoplasm of enveloping Schwann cell (sheath is formed by layers of modified cell membranes) x in CNS: cell process of oligondrocytes form sheath
nodes of Ranvier and internode, 1-2 mm
Schmidt-Lanterman´s incisures

29. Nerve fibres
axons provided by special connective tissue capsules of ectodermal origin
axons:
unmyelinated
myelinated

30. Astrocytes (protoplasmic, fibrous)
the largest of neuroglia
astrocytic end feet- connection to vessels and neurons providing movement of wastes and metabolites to and from neuron
regulate ionic concentration in intercellular space
contribute to blood-brain barrier
(together with tight junctions of endothelal cells)
mechanical support of neurons
proliferation - glial scar
glial fibrillary acidic protein

31. Oligodendrocytes smaller, ↓intermediate fibres, darker nucleus
formation of myelin sheath
myelinisation of several axons

32. Microglia the smallest, dark elongated nucleus
they migrate to the sites of dead cells, proliferate, phagocytes (dead cells, cell debris…)
mesoderm -derived

33. Ependym epiteloid arrengement uspořádání remnant of neuroepithelium of
neural tube
* secretory elements (cerebrospinal fluid)
component of choroid plexus of brain ventricles and central canal of spinal cord

34. Unmyelinated nerve fibres

35. N8 – Ganglion HE
Satelite cells
Neuron

36. Arrangement of nerve tissue in the body, CNS and PNS
clusters of neurons – cell body: layers, columns (grey matter)
bundles of axons: tracts, fasciculi, lemnisci (white matter)
(grey and white matter differentiation: according to the content of myelin)
PNS
clusters of neurons: ganglia
bundles of axons:
cranial
spinal
peripheral nerves