Specimen Nr. 12

Specimen:

Connective tissue (Sheep)

Staining:

TEM

Magnification:

13200x

Important structures :

1.Necrotic cell
2.Cell processes surrounding a necrotic cell
3.Nucleus
4.Rough endoplasmatic reticulum
5.Golgi apparatus
6.Lysosomes
7.Extracellular matrix
Dieses elektronenmikroskopische Bild zeigt einen Makrophagen bei der Phagozytose einer abgestorbenen Zelle. Mit dünnen Zytoplasmaausläufern umgreift der Makrophage zangenartig das tote Zellmaterial, das zum Teil engen Membrankontakt hat. Der kappenförmige Zellkern dieses Makrophagen liegt exzentrisch. Neben den Zisternen des rauhen endoplasmatischen Retikulum, einem ausgedehnten Golgi-Feld und Mitochondrien fallen vor allem zahlreiche Vesikel und Vakuolen mit osmiophilen Einschlüssen auf, die Lysosomen darstellen.

Legende:

Necrotic cell
Cell processes surrounding a necrotic cell
Nucleus
Rough endoplasmatic reticulum
Golgi apparatus
Lysosomes
Extracellular matrix

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.

Die Makrophagen gehören zum MPS (System mononukleärer Phagozyten). Das MPS umfaßt:

Weiterhin gehören zu diesem System:

Home
Tutor
Help
Exit
Boxes
Necrotic cell
Cell processes surrounding a necrotic cell
Cell processes surrounding a necrotic cell
Nucleus
Rough endoplasmatic reticulum
Golgi apparatus
Lysosomes
Lysosomes
Lysosomes
Extracellular matrix

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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