Specimen Nr. 03

Specimen:

Alveolar septum, lung (Mouse)

Staining:

TEM

Magnification:

15 000x

Important structures :

1.Capillary lumen
2.Erythrocyte
3.Endothelial cells of capillary
4.Alveolar saccule
5.Pneumocyte type I (type I alveolar cell )
6.Nucleus of pneumocyte type II
7.Nucleus of endothelial cell
8.Alveolar macrophage
9.Elastic fibres
Es ist die Grenzfläche zwischen Alveolarsäckchen und Lungenkapillaren abgebildet. Die Lungenkapillaren sind gut an den elektronendichten Erythrozyten zu erkennen, die sich in ihrem Lumen befinden. Die Kapillarendothelzellen kleiden die Wand lückenlos mit ihren platten Zytoplasmafortsätzen aus. Nur an Stellen, wo sich der Endothelzellkern befindet, ragen sie ins Lumen. Die Wand der Alveolarsäckchen besteht aus Pneumozyten vom Typ 1 und vom Typ 2. Die Typ 1- Pneumozyten, die langgestreckte Zytoplasma-Ausläufer besitzen, grenzen an die Atemluft.
Die größeren Pneumozyten vom Typ 2 sind meist in Nischen, wo mehrere Alveolarsäckchen aneinandergrenzen, zu finden. Als dritter Zelltyp sind die Alveolarmakrophagen zu sehen.

Legende:

Capillary lumen
Erythrocyte
Endothelial cells of capillary
Alveolar saccule
Pneumocyte type I (type I alveolar cell )
Nucleus of pneumocyte type II
Nucleus of endothelial cell
Alveolar macrophage
Elastic fibres

Blood-gas-barrier[bo]

1. Alveolar lumen
2. Alveolar pneumocyte type I (type I alveolar cell)
3. Alveolar pneumocyte type II (type II alveolar cell)
4. Capillaries
5. Basal lamina
6. Connective tissue
7. Alveolar macrophage

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 Grenzfläche zwischen Alveolarsäckchen und Lungenkapillare, auch Blut-Gas-Schranke genannt, wird von drei Schichten gebildet:
  1. einem einschichtigen, lückenlosen Alveolarepithel
  2. einem dünnen, lückenlosen Kapillarendothel
  3. der zwischen beiden liegenden Basalmembran
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Capillary lumen
Capillary lumen
Erythrocyte
Endothelial cells of capillary
Alveolar saccule
Alveolar saccule
Pneumocyte type I (type I alveolar cell )
Pneumocyte type I (type I alveolar cell )
Nucleus of pneumocyte type II
Nucleus of endothelial cell
Alveolar macrophage
Elastic fibres

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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