Morphological features of the feral pigeon’s (Columba livia f. urbana) digestive system

Abstract

Peculiarities of the morphological structure of the feral pigeon’s (Columba livia f. urbana) digestive system have been established. In the process of evolution, the digestive system has acquired certain anatomical changes that perform adaptive mechanisms for flying and egg-laying. In pigeons, the rostral part of the skull is represented by a beak consisting of an upper bill (maxilla) and gnathotheca (mandible) part. Due to the absence of a palatal fold, the digestive tract begins with the oropharynx, which lacks lips, teeth, and gums. The gorge is present in both sexes, consists of the right and left parts, and performs the function of accumulating fodder and secreting gorge milk, which is fed to the young through regurgitation. The mucous membrane of the esophagus forms longitudinal folds. There is a large number of digestive glands in the proventriculus. The cavity of the muscular stomach contains gastroliths, which act as teeth, ensuring grinding of food mass. The small intestine consists of the duodenum and ileum, which are joined by the mesentery and form three loops. The mucous membrane is developed, represented by numerous crypts that ensure the absorption of nutrients. The large intestine is represented by the paired rectal cecum and the rectum. The mucous membrane of the thick intestine is represented by leaf-like villi. The muscle layer is the most developed, myocytes are located in circular and longitudinal directions, forming folds