Specimen Nr. 02

Specimen:

M-cell of Peyer's patches, small intestine (Pig)

Staining:

TEM

Magnification:

10000x

Important structures :

1.Intestinal lumen
2.Zytoplasma of M (microfold) cell
3.Zytoplasma of enterocytes
4.Enterocytic microvilli (brush border)
5.Cell nucleus of an intraepithelial lymphocyte
6.Cytoplasm of a lymphocyte
7.Intercellular cleft between M cell and lymphocyte
Elektronenmikroskopische Aufnahme einer M-Zelle aus dem Dom-Epithel einer Peyerschen Platte im Dünndarm weist, im Gegensatz zu den Enterozyten, an ihrer apikalen Membran keine Mikrovilli auf. An der basolateralen Oberfläche besitzt sie tiefe Einbuchtungen, in denen Lymphozyten zu finden sind.

Legende:

Intestinal lumen
Zytoplasma of M (microfold) cell
Zytoplasma of enterocytes
Enterocytic microvilli (brush border)
Cell nucleus of an intraepithelial lymphocyte
Cytoplasm of a lymphocyte
Intercellular cleft between M cell and lymphocyte

Localisation of organs of immune-lymphatic system[we]

1. Pharyngeal tonsil
2. Palatine tonsil
3. Lymph node
4. Lymphatic vessels
5. Spleen
6. Peyer's patches
7. Thymus

Transmission electron microscope (TEM)

The sections for examination under the transmission electron microscope are about 0.1µm thick. They are referred to as ultra-thin sections.

To obtain such ultra-thin sections, the tissues are embedded in plastic polymers like epon (instead of paraffin, which is used for examination under the light microscope) after fixation and dehydration. Ultra-thin sections are not stained with dyes, but contrasted with heavy-metal salts. The heavy-metal salts lead to a different electron scatter and thereby create a differentiated blackening of the photographic negative. A common method of creating contrast results with 5% uranyl acetate and lead citrate.

Die M-Zellen des Dom-Epithels transportieren Antigen vom Lumen zum lymphatischen Gewebe. Dadurch können große Moleküle trotz der Epithelbarriere in Kontakt mit Zellen des Immunsystems gelangen und so Immunantworten initiiert werden. Auch das Fehlen von Schleim und IgA erleichtert die Bindung von Antigenen aus dem Darmlumen am Dom-Epithel. In den Peyerschen Platten werden in großem Ausmaß neue Lymphozyten gebildet.
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Intestinal lumen
Zytoplasma of M (microfold) cell
Zytoplasma of M (microfold) cell
Zytoplasma of enterocytes
Zytoplasma of enterocytes
Enterocytic microvilli (brush border)
Enterocytic microvilli (brush border)
Cell nucleus of an intraepithelial lymphocyte
Cytoplasm of a lymphocyte
Intercellular cleft between M cell and lymphocyte

HistoNet2000 - Help

1. Organization of the screen surface

Right side: histologic specimen
Left side: information about the specimen (above) and general program functions (below)

2.Histologic specimen

Pull the mouse across the histologic specimen for training purposes. A small square with exclamation marks (dynamic labels) will appear where there is an important structure. You should then decide what structure this could be. To check your result, simply click the appropriate square, and the correct label will appear. The option “marked” allows you to see all labels for all structures simultaneously. These can be removed by clicking “unmarked”. This reactivates the dynamic labels.

3. Complementary information

Info: general information about the specimen, as well as a list of the dynamic labels
Drawing: schematic drawing of the specimen
Staining: information about the staining method for this specimen
Knowledge: short texts with basic histologic information, presently deactivated

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