Specimen Nr. 05

Specimen:

Vermiform appendix (Human being)

Staining:

H&E

Magnification:

25x

Important structures :

1.	Intestinal lumen
2.	Epithelial layer of mucous membrane
3.	Lamina propria of mucosa
4.	Submucosa
5.	Muscular layer (Circular layer)
6.	External longitudinal smooth-muscle layer
7.	Serosa (Peritoneum)
8.	Germinal centre of a lymphoid follicle (secondary follicle)
9.	Area of M (microfold) cells
10.	Interfollicular area

Die Übersichtsvergrößerung zeigt die einzelnen Schichten der Wand des Wurmfortsatzes. Die Lamina epithelialis der Tunica mucosa zeigt die für die Dickdarmschleimhaut typischen Krypten. Lamina propria mucosae und Tela submucosa enthalten viel lymphatisches Gewebe, das an manchen Stellen auffällige Lymphfollikel bildet. Die Follikel sind stets Sekundärfollikel mit einem aktiven Keimzentrum. Eine besondere Region der Sekundärfollikel ist eine kappenartige Ansammlung von Lymphozyten zum Darmlumen hin, die Dom genannt wird. Zwischen den Follikeln liegt die Interfollikularregion. Die Tunica muscularis weist ein Stratum circulare und ein Stratum longitudinale auf. Außen schließt sich die Tunica serosa an.

Legende:

	Intestinal lumen
	Epithelial layer of mucous membrane
	Lamina propria of mucosa
	Submucosa
	Muscular layer (Circular layer)
	External longitudinal smooth-muscle layer
	Serosa (Peritoneum)
	Germinal centre of a lymphoid follicle (secondary follicle)
	Area of M (microfold) cells
	Interfollicular area

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.

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!