Scanning electron microscopy and histomorphology of the epiglottis in dromedaries: A study revealing unusual structure with the probable functional role.

While epiglottis is essentially a mammalian structure, studying its microstructure in any placental model will add an important information to the field of comparative anatomy and the related branches of biology. The aim of this study was to describe the structure of the epiglottis in dromedary camels using light and scanning electron microscopy (SEM), with reference to the possible functions. A total of 11 epiglottis cartilages from 11 larynges were used. The study revealed unusual, deeply situated glands just beneath the cartilage plate. They have unusually, wide surface-openings, while their ducts were partly located within the cartilage. This is presumed to be an adaptation to the need for rapid and efficient mucosal surface hydration in the arid conditions. The possible secretion transport mechanisms in these glands were also discussed. Furthermore, the SEM revealed for the first time, the presence of taste buds in camel epiglottis. However, in histological sections, visibility of taste buds was dependent upon the staining techniques. The taste buds were not seen with standard H& E stain, as they blended imperceptibly with the surrounding epithelium. Conversely, Mallory's trichrome showed contrasting colors, and taste buds were visible. In conclusion, camel epiglottis has an unusual structure, which may be correlated to environmental adaptation and important for the general health of upper respiratory tract in this species.