List of abbreviations |
Vocabulary
of micros- copic anatomy specialist terms explained in English + German |
Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected! |
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Conditions of use |
1. inner limiting membrane
= Stratum limitans internum (--> images)
borders the vitread body (Corpus vitreum) with a basal
lamina which has considerable regional differences in thickness,
radial
fibres spread above the basal lamina which are the endings ofMüller
Glial cells. They are connected to each other via small
tight
junctions just above the basal lamina.
2. nerve fibre layer = Stratum neurofibrarum (--> images) virtually all non-myelinated axons which form the optic nerve at the papilla, further some blood vessels are present here 3. ganglion cell layer = Stratum ganglionicum (--> images) with multipolar ganglion cells, which are the third neurons of the visual pathway 4. inner plexiform layer = Stratum plexiforme internum (--> images) contains the synapses between the second (bipolar cells) and the third neurons (ganglion cells) of the visual pathway. Most of these synapses are ribbon synapses with synaptic bodies, further many conventional chemical and a few electrical synapses are present here. 5. inner nuclear layer = Stratum nucleare internum (--> images) with perikarya of A. bipolar cells (rod- and cone bipolar cells = second neurons of the visual pathway which can be further callsified in many fuctionally different types), B. some amacrine cells, which are located at the border to 4, C. horizontal cells, which are also less frequent and located at the border to 6. Some of the horizontal cells show very large aggregated macrotubules in their cytoplasm. D. some intermingeled nuclei of radial fibre cells, i.e. Müller's glial cells. 6. outer plexiform layer = Stratum plexiforme externum (--> images) Processes of horizontal and bipolar cells are invaginated into the terminals of the photoreceptor cells (rods and cones) that show special electron-dense cell organelles, the synaptic ribbons, close to their presynaptic membranes in this area. The resulting ribbon synapses serve for ultrafast (tonical) signal transduction to the dendrites of the second neurons of the visual pathway (rod- or cone bipolar cells). Two bizarrely formed horizontal cell processes with terminal swellings are present in one invagination of rod terminals that often is subdivided in two endings. Whereas these horizontal cell terminals are located laterally, 1 - 3 thin bipolar cell processes comprise the centre of a ribbon synapse. In contrast to that cone terminals always show 25 up to over 50 invaginations with usually two lateral horizontal cell processes around 1 - 2 short bipolar cell dendrites. Apart from the majority of ribbon synapses, conventional chemical synapses are present outside the invaginations. Electrical synapses (gap junctions) are rare in this layer. 7. outer nuclear layer = Stratum nucleare externum (--> images) with the nuclei of the photoreceptor cells (rods and cones = first neurons of the visual pathway) 8. outer limiting layer = Stratum limitans externum (--> images) area with special belt desmosomes (Zonulae adhaerentes) located between the receptor cells and the very narrow terminals of Müller's glial cells 9. layer of inner and outer segments of rods and cones = Stratum segmentorum externorum et internorum (--> images) upper part: inner- and lower part: outer segments of rods and cones. The Ellipsoid is the part of the inner segment of a photoreceptor that is closer to the outer segment. It is very rich in mitochondria, shows some root fibres, wave-like bundles of intermediate filaments and microtubules. The ellipsoid continues into the Myoid, the lower part of an inner segment which is rich in Golgi-apparatuses and RER but hardly shows any mitochondria. The inner and outer segments are surrounded by a liquor filled space into which long, thin processes of Müller's glial cells reach from outside whereas from inside other long, thin processes of pigment epithelial cells protrude. The outer and inner segments are connected to each other only via a narrow cytoplasmatic bridge containing a cilium with 9x2 + 0 microtubules. 10. pigment epithelium (Stratum pigmenti = Pars pigmentosa; --> images) with pigment epithelial cells which phagocyte the tips of the rod or cone outer segments. The incorporated parts of the outer segments condense further and finally may no longer be distinguished from nearby pigment vesicles which prevent reflection of photons from incomeing light. Vast amounts of smooth endoplasmic reticulum are characteristic for the cuboid pigment epithelial cells. The junctional complexes between these cells are rich in tight junctions and the morphological base for the blood-retina barrier. Underlying Bruch's membrane, a rather thick basement membrane with lots of elastic and collagen fibres comprises the border to the Lamina choroidocapillaris (--> images) which has lots of blood vessels. The subsequent choroidea shows pigment epithelial cells scattered in loose connective tissue with an abundance of smaller blood vessels (especially fenestrated capillaries and venoles). The outermost layer of the ocular bulb is the strong sclera which consists of thousands of very tight parallel ordered collagen fibre bundles. |
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Overview with a part
of the nerve fibre layer |
Müller cell processes with
wide intercellular spaces |
2 Müller cells in
a basal location |
inner limiting mem-
brane proper |
detail: thick
basal lamina |
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Müller cell process
and nerve fibres |
nerve fibre layer
overview (X-section) |
detail thereof with
Müller glia cell |
further detail
thereof |
non-myelinated axons
of ganglion cells |
nerve fibre layer overview
in longitudinal section |
nerve fibre layer in an
oblique overview |
detail: dark mitochondrium of the crista-
type in the axon of a ganglion cell |
Müller's glia cell 1 | Müller's glia cell 2 |
ganglion cells
overview |
ganglion cell 1 | cytoplasm thereof | ganglion cell 2 | Müller cell +
ganglion cells |
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inner plexiform
layer 1 |
detail of the inner
plexiform layer |
inner plexiform
layer 2 |
Puncta adhaerentes of the
inner plexiform layer 1 |
Puncta adhaerentes of the
inner plexiform layer 2 |
synaptic bodies (ribbons and spheres) in
axons of bipolar cells (animation) |
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Overview | horizontal cell with
Macrotubuli aggregati |
nuclei of bipolar
and Müller cells |
nuclei of
different cells 1 |
nuclei of
different cells 2 |
rod bipolar cell with an ectopic synaptic
ribbon in a dendritic process |
cone bipolar cell with large dendrite |
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nuclei of
different cells 3 |
amacrine cell 1 | amacrine cell 2 | nucleus of an
amacrine cell |
nuclei of 2 bipolar cells | centriols of a
bipolar cell |
detail thereof | bipolar cell nucleus |
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rod terminals, outer
plexiform layer |
crystal close to a
ribbon synapse |
detail: crystal | rod terminal
(4 h post mortem) |
cone & rod terminals
serial image 1 |
cone & rod terminals
serial image 2 |
cone & rod terminals
serial image 3 |
ribbon synapses
rods & cone |
cone terminal with multiple
SBs, outer plexiform layer |
1 cone- & 4 rod terminals | stereo animation of a rod ribbon synapse | ribbon synapses and postsynaptic processes of a cone |
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overview with cone
nucleus and axon 1 |
detail thereof:
axon hillock 1 |
other cone nucleus with
axon hillock 2 |
detail thereof:
axon hillock 2 |
similar detail | nuclei mainly of rods | detail thereof |
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oblique section of the zonulae
adherentes of the outer limiting membrane |
Stratum limitans ex-
ternum (X-section) |
outer nuclear layer,
inner segments |
detail myoid, Stratum
limitans externum |
similar detail | rods: inner segments + nuclei
(fixed 4 h post mortem) |
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inner + outer segments
of a cone + rods |
detail: membrane
stacks of the cone |
detail: border of
inner + outer segment |
detail thereof | further detail | complete rod
outer segment |
rod cilium and
outer segment |
inner and outer
segments of rods |
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outer segments +
pigment epithelium |
pigment epithelial
cell |
phagocytosis of outer seg-
ments in pigment epithelium |
detail thereof | similar detail | pigment epithelial cell
SER, cytoplasm 1 |
pigment epithelial cell
SER, cytoplasm 2 |
detail: smooth endo-
plasmic reticulum |
Bruch's membrane |
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pigment cell of the choroidea | Bruch's membrane pig-
ment epithelium\choroidea |
overview thereof | Bruch's membrane (pigment
epithelium - choroidea) |
--> Presentation: 3D reconstruction
of „synaptic bodies“ in cones, rods & bipolar cells of the human retina
--> eye, synaptic bodies,
nerve
tissue, sensory organs
--> retina of mammals, rare organells
of human horizontal cells: Macrotubuli aggregati
--> Electron microscopic atlas Overview
--> Homepage of the workshop
I am very grateful to N. Ardjomand, E. Haller-Schober,
M. Theisl (university clinic Graz, Austria) & Prof. B. Stoffelns (university
eye clinic Mainz, Germany) for specimens. Images, page & copyright
H. Jastrow.