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.