Comparitive histological and histochemical study of the tongues of some vertebrate animals

Abstract EN

The present work is a comparative histological and histochemical study of the tongues of some vertebrate classes of amphibia (Rana temporarial reptilia (Mabuva quinquetaeniata.

Agama stellio), aves (Ardeola ibis) and mammalia (Rattus norvegicus).

Several pieces of the tongues of these animals were sectioned and fixed in Bouin's fluid, dehydrated, cleared, and embeded in paraffin wax.

Histological sections were cut at l]iva thickness and stained with hematoxylin and eosin.

The sections were also subjected to Alcian blue & PAS and mercury bromophenol blue sections to demonstrate the total protein contents.

The tongues are covered with sratified squamous epithelium which were projecting in the dorsal surface to form prominent lingual papillae having various shapes, sizes and different from one class to another.

The prevalent ones were filiform, foliate, fungiform and circumvallate papillae.

The papillae appeared clearly in the upper surface of the tongue of Rattus norvegicus.

in addition to the taste buds present in the area between the fungiform, foliate and circumvallate papillae.

The tongue of Ardeola ibis is much stronger than all those of the animals which were studied in the present work,due to the presence of skeletal element (the osentoglossus) in the submucosa of the tongue.

The tongue of Agama stellio is much stronger and more muscular than Mabuva quinquetaeniata and the lingual glands are purely mucous in nature in the latter but are mucous and serous in Agama stellio.

This difference is due to variations in food and feeding habits in the two species on one hand, and to the dry enviromental conditions of the desert life on the other hand.

The lingual glands, observed at the posterior part of their tongues are arranged in two groups, one is serous type and the other is mucous in nature and contains acid mucopolysacchrides.