Das proximale Tibiaende eines fetalen Kniegelenks zeigt im Bereich der Epiphysenfuge zahlreiche sekundäre Ossifikationszentren. Zwischen Epiphyse und den Knochenbälkchen der Diaphyse befindet sich die Epiphysenfuge, in dem die enchondrale Ossifikation abläuft.

Beachte: Die Knochenmanschette der Diaphyse, die z.T. angeschnitten ist, ist durch perichondrale oder desmale Verknöcherung entstanden!

Legende:

	Resting zone of epiphysial cartilage
	Epiphyseal plate
	Perichondral bone anulus
	Diaphysial bone trabecula and bone marrow
	Secondary ossification centre

Hematoxylin and Eosin (H&E)

H&E is the most common survey stain, which shows cell nuclei and cytoplasmatic components.

Structures	Colour
Nuclei	blue
Cytoplasm	pale red
Connective-tissue fibres - Collagen - Reticular - Elastic	red - pale rose to red
Muscle tissue	red
Erythrocytes	red-orange

Dyes:

Hematoxylin

(e.g. hemalaun, Weigerts or Heidenhains iron-hematoxylin)
Hematoxylin is a positively charged dye (at low pH values). It therefore colors negatively charged (basophilic) structures blue, like the DNA of nuclear chromatin, the RNA of rough endoplasmatic reticulum, and the acidic glycosaminoglycans of hyaline cartilage.
Hematoxylin used in the preparation of iron varnish is Weigerts or Heidenhains iron-hematoxylin and in the preparation of aluminum varnish is hemalaun.

Eosin

Eosin is a negatively charged dye used for counterstaining. It stains all remaining structures different shades of red (acidophilic).

Thiazinrot

Thiazinrot behaves similar as eosin.

Man unterscheidet primäre und sekundäre Ossifikationszentren:

Das primäre Ossifikationzentrum entsteht in der Diaphysenmitte. Durch das Periost und die Knochenmanschette dringen Blutgefäße und osteogenetische Stammzellen (=Knochenvorläuferzellen) in die nach dem Untergang der Chondrozyten zurückgebliebenen Hohlräume ein.
Die sekundären Ossifikationszentren befinden sich im Epiphysenknorpel und werden bei den meisten Knochen erst extrauterin angelegt (Ausnahme Tibia!).

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!

Specimen Nr. 02B

Specimen:

Staining:

Magnification:

Important structures :

Legende:

Hematoxylin and Eosin (H&E)

Dyes:

HistoNet2000 - Help