Brief Overview about Antenatal and Postnatal Development of Thyroid Gland of the Rabbit

Abstract

Background: The rabbit is considered one of the most widely distributed animal species used in economical purposes and laboratory studies. As the rabbit is considered a good source for meat and für production also, it is a model for research in the biological, physiological, and medical fields. In vertebrates, the pharyngeal apparatus is formed from transient series of segmental aggregations appearing as bulges on the craniolateral side of the embryo termed the pharyngeal or branchial arches. The endodermal epithelium of the pharyngeal pouches differentiates into number of important structures called branchiogenic or pharyngeal organs which include components of the lymphatic and endocrine systems such as thyroid, parathyroid glands, ultimobranchial body and thymus. The thyroid gland of rabbit is a butterfly-shaped organ composed of two symmetrical right and left lobes, connected via the isthmus. It is situated on the anterior side of the neck, ventral to the trachea connects with cricoid cartilage, and related to the common carotid arteries. The rabbit thyroid gland is surrounding by thin capsule of collagen fibers and its parenchyma subdivided into lobules composed of variable sized follicles.