Specimen Nr. 05

Specimen:

Loose connective tissue, Knee joint (Sheep)

Staining:

TEM

Magnification:

9200x

Important structures :

1.Collagen fibres (mostly obliquely sliced)
2.Collagen fibres (cross section)
3.Fibroblast with nucleus
4.Mitochondria of a fibroblast
5.Cell processes of fibroblasts
Die Ultrastruktur des lockeren faserigen Bindegewebes zeigt hier zwei seiner Hauptbestandteile: Fibroblasten und kollagene Fasern. Zwischen den unterschiedlich angeschnittenen kollagenen Fibrillen (längs, quer, schräg) liegen zahlreiche Fibroblasten mit den typischen Zellorganellen, wie rauhes endoplasmatisches Retikulum, Golgi-Komplex und Mitochondrien. Oft sind die Fibroblasten auch nur angeschnitten bzw. ihre langen, verzweigten Zellfortsätze zu erkennen.

Legende:

Collagen fibres (mostly obliquely sliced)
Collagen fibres (cross section)
Fibroblast with nucleus
Mitochondria of a fibroblast
Cell processes of fibroblasts

Loose connective tissue[kr]

1. Fibroblast
2. Fibrocyte
3. Single collagen microfibrils
4. Bundle of collagen microfibrils
5. Elastic fibres

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.

Man unterscheidet zwei Arten von faserigem Bindegewebe: lockeres faseriges Bindegewebe und straffes faseriges Bindegewebe. Zwischen den beiden Formen ist ein fließender Übergang. Beide Arten werden durch das Verhalten und die Erscheinungsform von Fasern und Zellen bestimmt:

Lockeres faseriges Bindegewebe enthält mehr fixe und freie Bindegewebszellen, während beim straffen faserigen Bindegewebe die Faseranteile überwiegen.

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Collagen fibres (mostly obliquely sliced)
Collagen fibres (mostly obliquely sliced)
Collagen fibres (cross section)
Fibroblast with nucleus
Mitochondria of a fibroblast
Cell processes of fibroblasts
Cell processes of fibroblasts

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

4. General Program Functions

Home: returns you to the “start” page
Tutor: how to contact the HistoNet Team
Help: Instructions for Use appear
Exit: closes down the HistoNet program
Boxes: goes back to the other specimen of a topic
VM: provides virtual microscopy

We hope you will enjoy working with HistoNet2000 and learn a lot from it!

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