Main anatomical and histological features of the tonsils in the camel (Camelus dromedarius)

Abstract

The tonsils, located around the pharyngeal cavity, constitute the first defence barrier against intruding microorganisms and antigens. The present work aimed to study the anatomical and histological aspects of camel tonsils in order to elucidate their role. The study was carried out on 12 camel heads fixed by infusion with 10 % neutral buffered formalin. A careful dissection of the oral cavity, the soft palate and the pharynx was conducted to explore the morphological aspect of different tonsils. Sagittal sections of some camel heads were also performed to explore their internal conformation, whereas the histological study was carried out on five specimens. All the six types of tonsils exist in the camel. Compared to other domestic species, they are well developed and all visible particularly the palatine one. The lingual, palatine, velar and paraepiglottic tonsils are arranged into closely assembled lymphoid follicles and show multitude crypt opennings into the oropharyngeal tube. The crypts epithelium is infiltrated with lymphoid cells allowing close contact with antigens. While the nasopharynx tonsils (pharyngeal and tubal) include loosely connected follicles which extend into the overlaying epithelium. The relatively great development and particular arrangement of the tonsils in the camel as well as the abundance of cryptic formations in all these tonsils constitute another aspect of adaptation and resistance of this species to its environment.