Gross morphological and histological features of larynx in Yankasa sheep (Ovis aries)

Abstract

The present study, conducted on the larynx of five adult Yankasa sheep was aimed at exploring its basic anatomy and histological features. The larynx consists of four cartilages; the unpaired epiglottis rostroventral, unpaired thyroid ventrally, dorsal paired arytenoid, and caudal unpaired cricoid. These cartilages presented distinct morphological features and were connected to each other by ligaments. The intrinsic laryngeal muscles include; the dorsal cricoarytenoid and transverse arytenoid muscles. The lateral cricoarytenoid was concealed by the thyroid laminae. The ventrally located thyroarytenoid and cricothyroid muscles. The laryngeal cavity comprised of rostral vestibule, a narrow middle glottic cleft and a wide infraglottic cavity caudally. Histologically, the epiglottis was lined by stratified squamous keratinized epithelium, the thyroid cartilage was lined by pseudostratified columnar epithelium, whereas the arytenoid cartilage was lined by pseudostratified columnar ciliated epithelium with goblet cells. The irregular loose connective tissue of the propria submucosa comprised of connective tissue cells mainly fibroblast, and fine blood capillaries, whereas the deeper part presented glandular tissues, ducts, fat cells and cartilages. It is envisaged that the study has provided basic information on gross and histological feature of the larynx in the Yankasa sheep.