Specimen Nr. 02C

Specimen:

Knee joint (Human fetus)

Staining:

H&E

Magnification:

Important structures :

1.	Zone of resting cartilage
2.	Zone of cartilage proliferation (columns of chondrocytes)
3.	Zone of hypertrophic cartilage
4.	Zone of cartilage resorption and endochondral ossification
5.	Perichondral bone anulus
6.	Periost
7.	Bone trabeculae (endochondral bone) with cartilage remnants (violet)
8.	Haematopoietic bone marrow

Im Bereich der Diaphyse sind zahlreiche neugebildete Knochenbälkchen (enchondrale Ossifikation!) mit dazwischenliegenden Hohlräumen (primäre Markhöhle) zu erkennen. Die Epiphysenfuge (Wachstumszone) weist Zonen mit Chondrozyten verschiedener Entwicklungsstadien der enchondralen Ossifikation auf.

Legende:

	Zone of resting cartilage
	Zone of cartilage proliferation (columns of chondrocytes)
	Zone of hypertrophic cartilage
	Zone of cartilage resorption and endochondral ossification
	Perichondral bone anulus
	Periost
	Bone trabeculae (endochondral bone) with cartilage remnants (violet)
	Haematopoietic bone marrow

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.

Die histologische Differentialdiagnose enchondral von perichondral bzw. desmal entstandenem Knochen gelingt leicht auf Grund der Knochenmatrix:
Der enchondrale Knochen enthält Reste verkalkter, nicht vollständig abgebauter Knorpelmatrix die unregelmäßig konturiert und in der Regel anders als die Knochenmatrix gefärbt ist. Dem perichondralen bzw. desmalen Knochen fehlen diese nicht abgebauten Knorpelreste (Vergleiche Bezeichner 5 und 7 der Abbildung!)

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!