Histomorphological Study of Tongue in Moorhen (Gallinulla chloropus)

Abstract

Aims: The present investigation was carried out to offer fundamental information on the
morphological and histological structure of the tongue in moorhens (Gallinula
chloropus). For the current investigation to be carried out, seven moorhens were
purchased from the Baghdad, Iraq, commercial market. The samples(tongue) were then
carefully fixed in 10% neutral buffered formalin. The specimens were washed with tab
water then dehydrated with serial dilution of alcohol and cleared with xylene and then
embedded in paraffin wax. Following a five micrometer-thick sectioning, the slides were
stained with hematoxylin and eosin. according to the gross findings our results showed
that the tongue was situated on the floor of the oropharyngeal cavity. A row of caudally
pointed papillae arranged transversely known as lingual papillae separated the tongue's
rostral and caudal regions. There was a laryngeal cleft beyond it, with one pharyngeal
papillae row positioned caudally in a heart shape. There were a distinct keratinized bands
on the dorsal surface of the tongue apex, the lingual mucosa's histology revealed
stratified squamous epithelium with varying degrees of keratinization. Many mucosal
glands were seen in the caudal part of the tongue; the secretions emptied into the ducts,
this led to the tongue's dorsal surface opening. Whereas the papillae might act primarily
as physical barriers to the reflexive backward movement of food that has passed over
them, the glandular secretions may facilitate swallowing by lubricating the caudal region
of the oropharyngeal cavity in addition to the proximal part of the esophagus. The study
concluded that the morphological features of the moorhen's tongue are likely adaptations
adequate to its unique feeding habits and methods of gathering food. These adaptations
make the moorhen an excellent forager in ponds, marshes, and other wetland
environments, that has evolved a special beak and tongue to survive in its aquatic
environments. Small aquatic invertebrates and plant matter can be filtered and retained
from the water by its tongue by means of papillae, which are hair-like projections
pointing backward. Because of these adaptations, moorhens are great foragers in ponds,
marshes, and other types of wetland habitats.