[Functional morphology of the large intestinal mucosa of horses (Equus przewalskii f. caballus) with special regard to the epithelium].

This research investigates the structure and workings of the mucous membrane in the caecum and ascending colon of adult horses, particularly focusing on the epithelium. The discovery includes a large presence of mitochondria, significant intercellular spaces, single enteroendocrine cells in certain areas, and the absence of alkaline phosphatase activity, resulting in implications regarding the intake of water and electrolytes in horses’ large intestine.

Investigation of the Mucous Membrane

• The study conducted both light and transmission electron microscopy on the mucous membrane of the caecum and ascending colon in adult horses, which are parts of the digestive system in horses.
• An ‘inconspicuous constellation of organelles’ was noticed in the surface epithelium, a thin layer of cells forming an outer layer or covering, which seems to indicate there weren’t any particularly striking features or abnormalities detected.

Presence of Mitochondria

• The significant presence of mitochondria indicates that a considerable amount of energy is being generated in this area, likely due to its role in the absorption processes of the digestive system.

Intercellular Spaces and Water Uptake

• The enlarged intercellular spaces in the area imply an enhanced uptake of water and electrolytes. This observation may suggest that parts of the horse’s digestion or absorption process work differently from many other animals.

The Basal Region of Lieberkühn’s Crypts

• In the basal region of Lieberkühn’s crypts, single enteroendocrine cells were found. Enteroendocrine cells are a form of epithelial cells responsible for the secretion of various hormones in the gut. Numerous granules were also found in the apical epithelial cytoplasm, whose function is yet unclear and debated.

Lack of Alkaline Phosphatase Activity

• The lack of epithelial activity of alkaline phosphatase, an enzyme that breaks down proteins, despite a small positive reaction of adenosine triphosphatase at the lateral plasmalemata of the epithelial cells, is notable. Adenosine triphosphatase is an enzyme that aids in molecular transportation in cells.

Conclusion

• The findings of the study hint toward a unique mechanism for substance transport in the equine large intestine.