[2] The VNO contains the cell bodies of sensory neurons which have receptors that detect specific non-volatile (liquid) organic compounds which are conveyed to them from the environment.

A thin duct, which opens onto the floor of the nasal cavity inside the nostril, is the only way of access for stimulus chemicals.

During embryological development, the vomeronasal sensory neurons form from the nasal (olfactory) placode, at the anterior edge of the neural plate (cranial nerve zero).

[13][14] Upon stimulation activated by pheromones, IP3 production has been shown to increase in VNO membranes in many animals, while adenylyl cyclase and cyclic adenosine monophosphate (cAMP), the major signaling transduction molecules of the main olfactory system, remain unaltered.

This trend has been shown in many animals, such as the hamster, the pig, the rat, and the garter snake upon introduction of vaginal or seminal secretions into the environment.

[18] Detecting the types and amounts of different sulfated steroids conveys information about the urine donor's physiological state, and may therefore serve as an honest signal.

Recent studies proved a new family of formyl peptide receptor like proteins in VNO membranes of mice, which points to a close phylogenetic relation of signaling mechanisms used in olfaction and chemosensors.

The main olfactory sensory neurons fire single burst action potentials and show a much quicker adaptation rate.

Activating neurons that have V1 receptors, V1Rs, cause field potentials that have weak, fluctuating responses that are seen the anterior of the accessory olfactory bulb, AOB.

[19] In mammals, the sensory neurons of the vomeronasal organ detect non-volatile chemical cues, which requires direct physical contact with the source of odor.

[34] Some mammals, particularly felids (cats) and ungulates (which includes horses, cattle, and pigs among other species), use a distinctive facial movement called the flehmen response to direct inhaled compounds to the VNO.

[39] However, Smith and Bhatnagar (2000)[40] asserted that Kjaer and Fisher Hansen simply missed the structure in older fetuses.

[41] In a study using retrospective analysis of nearly one thousand outpatient nasal endoscopies, Stoyanov et al. (2016) found the organ to be present in 26.83% of the Bulgarian population.

[45] Among studies that use microanatomical methods, there is no reported evidence that human beings have active sensory neurons like those in working vomeronasal systems of other animals.

[46] Furthermore, there is no evidence to date that suggests there are nerve and axon connections between any existing sensory receptor cells that may be in the adult human VNO and the brain.