Structure and Function of Vomeronasal Organ

The olfactory organ is subdivided into the main olfactory organ and the vomeronasal organ in tetrapods.The vomeronasal organ,is an accessory olfactory organ that is found in many animals.The vomeronasal organ is cartilaginous capsules near the vomers and covers with the vomeronasal epithelium.The main olfactory organ mainly samples volatile substances,while the vomeronasal organ may be specialized for detecting non-volatile substances,such as pheromones.Nearly all vertebrates possess an olfactory organ.However,the presence or absence of the vomeronasal organ varies among vertebrates.The vomeronasal organ is present in tetrapods but is absent in fish,and among tetrapods is vestigial or absent in crocodilians,birds,most bats,and marine mammals.The vomeronasal organ is firstly present in amphibians.In snakes or rodents,the vomeronasal organ is very developed and becomes an independent organ.There is a considerable controversy that the vomeronasal organ is a water sampling or an air sampling organ.The origin and function of the vomeronasal organ has significant value for understanding the adaptation of the olfactory system during the transition from an aquatic to terrestrial life.