Vomeronasal organ: what is it, its location and functions?

This organ linked to the sense of smell is related to the uptake of pheromones.

The world of odors is fascinating. Although we are probably the least developed sense in humans, thanks to this sense we are able to perceive very diverse aromas that have different effects on us, and even taste what we eat.

But not all that we can capture when we inhale are odors. The vast majority of mammals have an internal organ capable of detecting pheromones. We are talking about the vomeronasal organ, which is common to a large number of mammals and whose existence and functionality in humans has often been discussed.

The vomeronasal organ: description and localization

We call vomeronasal organ to a structure present in a large number of living beings and in the human being (although depending on the study it is stated that it is part of all human beings or that only a percentage of them possess it), which serves as an auxiliary organ of the olfactory system. serves as an auxiliary organ of the olfactory system..

It consists of a group of sensitive receptors specialized in the capture of pheromones, chemical signals left by humans.It is a group of sensitive receptors specialized in capturing pheromones, chemical signals left by living beings that serve as a message to other beings, whether or not they are of the same species. These receptors are connected to bipolar neurons that have connections with the hypothalamus and the olfactory bulb.

The vomeronasal organ is also called the Jacobson's organ after Ludwig Lewin JacobsonJacobson, who gave it its original name (vomeronasal organ) after studying the structure that Frederik Ruysch had seen and described (being the first to do so) after observing a structure in the anterior part of the nasal septum of a corpse. Jacobson also visualized this organ in various animals and noticed a lack of development of this structure in the case of the human being.

In the human being this organ is a bilateral tube that can have several forms, being the most usual that of a conical sac, and that is located anteriorly to the vomer bone and below the respiratory mucosa. It is connected to the nasal cavity and is lined with epithelial tissue..

In many animals there is an internal pump formed by Blood vessels that, when contracted, allow pheromones to be absorbed and captured. However, this does not occur in humans, being a membranous organ that does not have a large vascularization.

Functions of Jacobson's organ

The existence of the vomeronasal organ is a reality in a great majority of terrestrial animals. The main function associated with this organ is that of capturing signals emitted by other members of the same species in order to transmit certain information. Pheromone uptake allows animals to choose reproductive partners with immune systems very different from their own (something that benefits possible offspring), to detect the health status of an animal of the same species, to warn potential sexual partners of the mating stage or to mark a social status.

Also is also very useful to many animals when detecting and hunting prey.The pheromones are also present in other animals, as in the case of ophidians (in fact, the typical movement of the snake's tongue contributes to bring pheromones into and closer to this organ).

However, in other animals it does not seem to present a functionality, as in the case of aquatic mammals (dolphins and whales) and certain species of bats and apes.

Functions in humans

With regard to humans, as mentioned above, their functionality has been highly debated. its functionality has been highly debated. Traditionally, the vomeronasal organ has been considered a vestigial organ inherited from our ancestors and without a role in our organism, like the coccyx, wisdom teeth or nipples in man.

However, it has been observed that exposure to certain pheromones in the human vomeronasal organ can generate physiological changes at the physiological level. can generate changes at the physiological level. In fact, it has been found that some aspects of our behavior or even our biology can depend on or vary through exposure to pheromones. The best known example is that of sexual attraction: there are people who, being strangers, we are instinctively attracted to, regardless of their physical appearance or personality.

There is another aspect that happens regularly and whose explanation is also hormonal: when several women live together continuously for a period of time, their menstrual cycles tend to synchronize. Likewise, the presence of males cohabiting with the woman can also alter the menstrual cycle. Similarly, it has been observed that exposure to certain hormones has been observed to relax behavior and decreases the level of aggressiveness in men, or may increase their testosterone level.

Finally, it is also known that there are certain pheromones emitted by mothers and babies that play a certain role in maternal-filial bonding and bonding. in the maternal-filial bonding and bonding and the behavior of either of them can be modified depending on the uptake of some of them by the vomeronasal organ.

Commercial exploitation of pheromones

However, it must be taken into account that the existence of this organ and of the role of pheromones in aspects such as sexual attraction in aspects such as sexual attraction has been exploited by a large number of brands to try to sell their products, selling different perfumes or even preparations with pheromones on a commercial level.

In this sense we have to take into account that first of all we ourselves already emit pheromones, and the mixture of our own pheromones with those of others can be confusing or even unpleasant, and we have to take into account that sexual and romantic attraction is not limited only to the hormones that we give off.

In addition, it must be considered that different pheromones can have different effects depending on who picks them up (for example, as we have said before at the level of sexual attraction is usually more appetitive someone with an immune system very different from ours).

Bibliographic references:

• Naser, A.; Fullá, J.M.; Varas, M.A.; Nazar, S. (2008). The human vomeronasal organ. Revista de otorrinolaringología y cirugía de cabeza y cuello, 68 (2). Santiago.
• Zeller, F.L. (2007). Normal anatomy and frequency of Jacobson's vomeronasal organ (VNO) in human fetuses. Rev. Argentina de Urología, 1 (72).