‘Flowers’ beneath the surface

Bryozoans - commonly called moss animals - form plant-like colonies. There are about 4000 species of bryozoans, which occur in both fresh and salt water, from the tropics to the polar regions. In this case the video shows a fresh water variety. They attach themselves to every conceivable surface providing grip. The colonies of bryozoans are formed by a large number of individual animals, which are also called zooids. Any zooid, which usually is not yet a millimeter in length, is locked up in a ‘shell’, which can be box-shaped, oval, vase-shaped or tube-shaped, depending on the shape of the colony.

No watch without a microscope

For years magnifiers and microscopes are needed for the manufacture and repair of watches. Who does not know the familiar image of the watchmaker wearing a magnifying glass for one eye. He is peering in stooped posture into the interior of a watch as if there is a big hidden secret inside.

A colon, why?

Human colon | SMZ171 stereomicroscope | Moticam 10

In the large intestine (colon) resorption takes place of the remainders of the digested food and liquid, which makes the stool thicker and makes it gliding by the addition of mucus. The wall of the large intestine consists of the typical layers for the digestive tract: the mucosa, submucosa, muscularis and serosa. The lumen is subdivided by numerous crescent-shaped folds.

Human colon | BA410E PlanAPO 10X | Moticam 10

The mucous membrane of the large intestine is a single layer of thick cylindrical epithelium, which consists of numerous absorptive cells with a brush-like edge, amongst which goblet cells are embedded. The latter do not have a brush-like edge and produce mucus especially at the bottom of the tubular crypts. The crypts are straight tubular and run down from the surface through the mucosa. With the depth, the number of goblet cells increases, while the absorptive cells become flatter and diminish in number. The connective tissue of the lamina propria fills the space between the crypts. The muscularis mucosa is composed of an inner ring and an outer layer of smooth musculature. The submucosa is a loose connective tissue with solitary lymph nodes, larger blood vessels and groups of fat cells.