Specimen Nr. 08

Specimen:

Connective tissue (Sheep)

Staining:

TEM

Magnification:

6600x

Important structures :

1.Nucleus
2.Nucleolus
3.Cell surface (with bizarre processes)
4.Primary lysosomes
5.Secondary lysosomes
6.Residual body
Makrophagen sind vielgestaltige, oft gelappte Zellen, die plumper als Fibrozyten wirken. Ihre Zelloberfläche ist reichlich gegliedert und weist zahlreiche bizarr gestaltete Zellfortsätze auf, die im Dienste der amöboiden Fortbewegung sowie der Phagozytose stehen. Im Zellinneren kommen neben den üblichen Zellorganellen (rauhes endoplasmatisches Retikulum, Golgi-Komplex, Mitochondrien) viele unterschiedliche osmiophile Vesikel und Vakuolen vor. Es handelt sich teils um primäre, teils um sekundäre Lysosomen. Auch zu Phagolysosomen und Restkörpern (Residualkörpern) umgestaltete Einschlüsse sind zu sehen.

Legende:

Nucleus
Nucleolus
Cell surface (with bizarre processes)
Primary lysosomes
Secondary lysosomes
Residual body

Monocytes

Monocytes are part of the immune system – the mononuclear phagocyte system. Chemotactic stimuli cause them to cross the capillary walls and enter the connective tissues, where they differentiate into macrophages. Here they can be found in both mobile and sessile (histiocytes) forms.

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.

Makrophagen oder Histiozyten (Synonyme: sessile Makrophagen, Gewebsmakrophagen, ruhende Wanderzellen) findet man regelmäßig im lockeren faserigen Bindegewebe. Sie liegen häufig kleinen Blutgefäßen an. Sie sind durch Umdifferenzierung aus Monozyten entstanden, nachdem diese die Blutbahn verlassen und ins Gewebe ausgetreten sind. Monozyten des Blutes reagieren chemotaktisch auf anfallendes nekrotisches Material, auf eindringende Mikroorganismen und auf Entzündungen. Sobald Monozyten das Blut verlassen haben, nennt man sie Makrophagen.

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Nucleus
Nucleolus
Cell surface (with bizarre processes)
Primary lysosomes
Secondary lysosomes
Residual body

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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