Macroscopic study of lymph nodes development in sheep fetus

Due to the importance of immune system and important roles of lymph nodes against pathogens and with regard to there were not any study about anatomy of lymph nodes in sheep fetuses, this research was conducted to study macroscopic developmental growth of lymph nodes in fetal period. Also, anatomical specifications and estimating time of formation of some important lymph nodes evaluated. For this purpose, sixty sheep fetuses collected from slaughterhouse of Ahvaz, after fixation in 10% formalin solution and sex determination, were divided into to four groups according to CRL. Mandibular, superficial cervical (prescapular), caudal mediastinal, jejunal mesenteric and popliteal lymph nodes from five lymphocenters included head, neck, thorax, abdominal viscera and pelvic limb was evaluated, respectively. In each sample, appearance formation of nodes was studied and in the case of formation, gross shape, location, and their number were checked. Minimum and maximum of fetuses CRL were detected 3.5 and 48.5 cm(43 to 138 days old). In 32 male and 28 female studied fetuses, Sexuality had no effect on checked parameters. Unusual observations were not recorded in location of the nodes. Study of the lymph nodes in sheep fetuses showed that before 59 days old, all lymph nodes were not been visible macroscopically and before 45 days old, none of lymph nodes were macroscopic developed.