Pheromones and the Nose

We live in an age where body scent is becoming more and more a determinant in choosing a sexual partner. However, there is still the question of why this is happening. It has long been a debate whether or not humans have a vomeronasal organ (VNO) or not. The VNO is located in the lower section of the nose. It receives the pheromones and sends a signal to the brain, stimulating sexual attraction. In the last few years scientists have discovered that humans do indeed give off pheromones. Scientists took sections of human skin and experimented on their scents. They put a special electrode inside the supposed spot for the VNO and they recorded spikes in neuron firing and a rise in hormone levels. Obviously, this means that humans do give off pheromones and they do have an effect on members of the same species. Another question involved in this process is how the VNO relays information to the brain. Scientists have found that animals have an accessory olfactory bulb that sends signals to the brain. As of right now they can't find this bulb in the human nose, but scientists believe that it may exist just in a different form. Researchers also believe that the cells in the VNO send signals to the hypothalamus which stimulates the pituitary gland in the release of hormones. These signals also change the activity of the neuroendrocrine system which regulates reproductive behavior. One of the other main questions is where do pheromones come from? Scientists have found that the answer may be our apocrine glands. What they have found is that humans have large concentrations of apocrine glands in their face and they only show up in the body after puberty. Another piece of evidence in support of the existence of human pheromones is that women who work or live in close proximity end up with synchronized menstrual cycles. The concensus for the cause of this phenomena are pheromones. It has also been proposed that our immune system has an effect on sexual attraction. Each human has their own specific major histocompatibility complex. The MHC codes for specific proteins that help fight off diseases and infections. Studies have shown that women choose men with an MHC completely different from their own. These same women also say that men with a similar MHC have a scent that reminds them of a relative. Another study on women showed that women who were taking birth control preferred the smell of a man with a similar MHC. One explanation for this is that birth controls trick a woman's body into thinking that they are pregnant and pregnant women have been known to prefer smells that remind them of home and loved ones. All of these studies show that we have only scratched the surface of human pheromone research.

Terms:
Olfactory bulb- the enlarged terminal part of each olfactory lobe from which the olfactory nerve originates.
Septum- a dividing wall, membrane, or the like, in a plant or animal structure; dissepiment.
Hypothalamus- a region of the brain, between the thalamus and the midbrain, that functions as the main control center for the autonomic nervous system by regulating sleep cycles, body temperature, appetite, etc., and that acts as an endocrine gland by producing hormones, including the releasing factors that control the hormonal secretions of the pituitary gland.

This report is simialr to one I found earlier, but it just goes to show that this information is accurate and widely accepted. We still have so much to learn and I could spend hours talking about it in my presentation, but I'm sure that just scratching the surface provides information that is just fascinating. There are some out there who still refute all of this evidence and claim that humans in fact do not produce pheromones and even if they did, they would have no effect on our sexual attraction. I guess they find that a little to barbaric and animal-like. However, with all the information and phenomena pouring in every day, it's getting harder to believe that this is all just a mistake. It's something we will continue to research and I'm sure new information will surface over the next ten years.