МЕДИЦИНСКАЯ АКАДЕМИЯ ИМЕНИ С.И. ГЕОРГИЕВСКОГО ФГАОУ ВО «КФУ ИМ. В.И. ВЕРНАДСКОГО»resenatation omeronasal

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rof. Zaichenko Alexander Ivanovich

PV

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Vomeronasal Organ

INTRODUCTION The vomeronasal organ (VNO), or the

Jacobson's organ ( latin - organum vomeronasale)

auxiliary olfactory sense organ - animals. It lies close to the vomer and nasal bones. Discovered by Frederik Ruysch prior to 1732

and later by Ludwig Jacobson in 1813. This organ is the sense organ involved in

the flehmen response in mammals.

FRONTAL SECTION OF NASAL CAVITIES OF A HUMAN EMBRYO 28 MM. LONG (VOMERONASAL ORGAN OF JACOBSON LABELED AT RIGHT)

TOPOGRAPHY

In Human

s

The Vomeronasal organ (VNO) is located in the nasal cavity on either side of the nasal septum in humans and animals. It can also be located near the roof of the mouth in some animals.

IN ANIMALS

The vomeronasal organ is very well developed in snakes, lizards and mice.

STRUCTURE

VNO -base of the nasal cavity. Divided by the nasal septum, C-shaped, or crescent, lumen. The vomeronasal receptor neurons possess axons which travel from the VNO to

the accessory olfactory bulb (AOB) or, as it's also known, the vomeronasal bulb. sensory receptors located on the medial concave surface of the crescent lumen.

The lateral, convex surface of the lumen is covered with non-sensory ciliated cells, where the basal cells are also found.

At the dorsal and ventral aspect of the lumen are vomeronasal glands, which fill the vomeronasal lumen with fluid

. Sitting next to the lumen are blood vessels that dilate or constrict, forming a vascular pump that deliver stimuli to the lumen. 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).

FUNCTION

Detects chemical compounds contained within scents.

Specifically chemical-communication signals (pheromones)

FLEHMAN RESPONSE

The flehmen response is a behaviour whereby an animal curls back its upper lips exposing its front teeth, inhales with the nostrils usually closed and then often holds this position for several seconds.

It may be performed over a site or substance of particular interest to the animal (e.g. urine or faeces) or may be performed with the neck stretched and the head held high in the air.

Flehmen is performed by a wide range of mammals including ungulates and felids. The behaviour facilitates the transfer of pheromones and other scents into the vomeronasal organ located above the roof of the mouth via a duct which exits just behind the front teeth of the animal.

FUNCTION OF FLEHMEN Identifying reproductive status

Reproductive synchrony

RESOURCES http://www.neuro.fsu.edu/faculty/mmered/vomer/human.htm http://chemse.oxfordjournals.org/cgi/content/full/26/4/433 http://www.abc.net.au/science/articles/2001/05/11/292

413.htm?site=science/greatmomentsinscience Pure Instinct Perfume• STRUCTURE AND FUNCTION OF THE VOMERONASAL

ORGAN, KJELL B. DØVING1,* ANDDIDIER TROTIER• http://serendip.brynmawr.edu/bb/neuro/neuro99/web3/Bernstein.htm

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Made By :- Abhijeet Kumar Srivastava

AndShubham Arora

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