Jacobson's organ

Jacobson's organ, or the vomeronasal organ, is a paired chemosensory structure that detects chemical cues, especially in many nonhuman vertebrates. Its anatomy and function vary across species.

Vomeronasal sensory neuron: A sensory neuron in the vomeronasal organ that detects chemical stimuli and sends signals to the brain. These neurons convert compounds entering the organ into neural signals.
Nasal cavity: The hollow space behind the nose through which air passes toward the respiratory tract. In many mammals, the vomeronasal organ lies near the nasal cavity.
Snake: A legless reptile in the suborder Serpentes. Many snakes use tongue-flicking to deliver environmental chemicals to the vomeronasal organ.
Ludwig Jacobson: A Danish surgeon and anatomist who described the vomeronasal organ in 1811. His name became attached to the organ after his anatomical description.
Vomeronasal duct: A passage connecting the vomeronasal organ with the nasal or oral cavity, depending on species. The duct is a route by which collected chemical cues enter the organ.
Chemoreception: The detection of chemical substances by specialized sensory cells. This broad sensory process includes the organ's detection of chemical cues.
Lizard: A diverse group of reptiles, mostly with four limbs and external ear openings. Many lizards sample chemical cues with the tongue and process them through this organ.
Frederik Ruysch: A Dutch anatomist whose work included an early description of the vomeronasal organ. Ruysch's earlier anatomical account preceded Jacobson's better-known description.
Tongue-flicking: A behavior in which an animal rapidly extends and retracts its tongue to sample chemicals from the surroundings. In snakes and some lizards, tongue flicks collect molecules that are delivered to the organ.
Olfactory epithelium: A tissue lining part of the nasal cavity that contains sensory neurons for ordinary smell. It provides a useful comparison with the organ's distinct sensory tissue.

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