Die Zellgrenzen der einzelnen Herzmuskelzellen des Reizleitungssystems sind nicht deutlich voneinander abgrenzbar. Ihr Sarkoplasma hat ein faserig-körniges Aussehen. Es enthält weniger Myofibrillen und Mitochondrien als die Arbeitsmuskulatur, ist aber reich an Glykogengranula. Die vielen Zellkerne im Bindegewebe gehören zu Fibrozyten und Lyphozyten. Vom Bindegewebe zu unterscheiden sind die in ihm liegenden Ansammlungen vegetativer Nervenfasern.

Legende:

	Cardiac conducting muscle cells
	Loose collagenous connective tissue
	Fibrocyte nucleus
	Light coloured nuclear corona
	Nerve fibres of enteric nervous system

Giesons trichromatic stain

This is the dye most commonly used to stain connective tissue.

Structures	Colour
Nuclei	black-brown
Cytoplasm	yellow-brown
Connective-tissue fibres - Collagen - Reticular - Elastic	red - yellow
Muscle tissue	yellow
Erythrocytes	yellow

Dyes:

Weigerts iron hematoxylin	This dye is one of the hematoxylins, but stains much more intensively than hemalaun. It is used with van Gieson’s dye to stain cell nuclei.
Picro-fuchsin or Picro-thiacid mixture	This dye solution simultaneously stains connective tissue red and muscle tissue yellow (simultaneous stain).

Die rhythmische Kontraktion des Herzens kommt durch Impulse in den modifizierten Muskelfasern des Reizleitungssystems zustande. Der Sinusknoten ist normalerweise der Schrittmacher. Die Schlagfrequenz des Herzens (normal 60-80/min) steht aber auch unter dem Einfluß der beiden Gegenspieler des autonomen (vegetativen) Nervensystems, dem Sympathikus und dem Parasympathikus. Eine Stimulation des Parasympathikus (Vagusreiz) verlangsamt den Herzschlag, die des Sympathikus steigert ihn.

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. 02C

Specimen:

Staining:

Magnification:

Important structures :

Legende:

Giesons trichromatic stain

Dyes:

HistoNet2000 - Help