The Sense of Smell and How it Works
We think of the nose as primarily an organ of smell. However, its main function is moderating the temperature of inhaled air, which protects the lining of the lungs. Secondarily, the nose serves as a conduit that guides scent into the olfactory system. Only about 2% of inhaled air reaches the olfactory epithelium, which consists of two patches of tissue, covering an air area of one square inch, in the upper rear of the nasal cavities. This is where we detect smell.
The olfactory nerve contained about 15 million smell receptors that protrude from mucous membranes. These hairs collect odors and convert them into messages which are relayed to the olfactory nerve and then to the brain for processing. Olfactory cells are the only nerve cells that are regenerated in the body.
Smell signals travel through the limbic system and play an important role in provoking feelings and memories. Among the structures that form the limbic system are the amygdala, where reprocess anger; the septum pellucidum, where we process pleasurable sensations; and the hippocampus, which regulates how much attention we give these emotions and memories.
Since the sense of smell has a powerful impact on memory, odor can evoke the recall of emotions. The subconscious mind stores our memories of past experiences in a memory bank.
When inhaling an aroma, the olfactory cells transmit a direct signal to the brain’s memory bank. As this process occurs, a particular memory may be activated. If the scent is recognized, it may trigger a memory of past events and emotions associated with that particular odor. The smell memory may also trigger changes in body temperature, appetite, stress level, and sexual arousal. This close connection between smell and memory may help determine why certain individuals prefer one scent to another.
The chemical substances in scents that affect reproductive behavior, and can’t as a sexual excitement are known as pheromones. Pheromones are present in perspiration, saliva, vaginal secretions, and urine.
The apocrine glands, mainly located in the armpits and around the groin, produce pheromones. These glands are largest during a persons reproducing years. Secretions from the apocrine glands are odorless, however; odor occurs only after bacteria present react to the perspiration.
In one study, perspiration collected from men’s under arms were swabbed three times a week on the upper lips of women whose menstrual cycles were less than 26 days or more than 33 days. (uhmm.yea, i don’t know if I would want to be part of this study. lol)
After three months, all the women cycles were regulated to 219.5 days – the optimum length for maximizing fertility. Menstrual cycles of women who live or work together become synchronized over a period of time. Many have speculated that this is due to a woman being exposed to another woman’s perspiration –(smelled over several months ) and then adapting to the other woman’s cycle. Men who are around woman who have more rapid hair growth, and women who are around men have more regulated cycles.
Women are particularly sensitive to the odor of pheromones, just before ovulation – about 1000 times more so than at any other time during her cycle.
The most acute sense of smell known is that of the Chinese Emperor moth, which can detect a scent. It recognizes over 6 miles away. The male silkworm moth comes in a distant second, with its ability to detect the odor of the female silkworm’s sexual secretion over 2 miles away. Although smell is not a highly developed human sense, smell remains nearly 10,000 times more sensitive than taste. Dogs are estimated to be over 1 million times more odor – sensitive than humans.
The connection between sex and sent an humans seems less important than it does for insects and animals. The pheromones that send in insect into a rage of passion do not affect humans the same way. Comparatively, humans do not demonstrate as intense or impulsive in response to scent signals from the opposite sex. Rats in the laboratory deprived of their sense of smell from birth, have low levels of growth hormones produced by the pituitary gland. Their growth. This started and their testicles are sub normal. One out of four people who suffer from an anosmia ((loss or impairment of the sense of smell) lose interest in sexual activity. Hamsters that cannot smell their mates entirely lose interest in them.
Anosmia affects 2 million people in the United States. Parosmia is a common abnormal tea that causes a distorted sense of smell. The perception of a given scent may be interpreted as a consistent bad smell, similar to fecal matter. Both conditions, Anosmia and Parosmia can result from head injuries or diseases.
Today, in our eagerness to deodorizer bodies and make them fragrant, we have disguised our natural odor communication. Nevertheless, we still communicate, but to a lesser extent, through our natural scents. To achieve a richer life, we must develop a greater understanding of how scents affect our health and behavior. Only then will we begin to appreciate this most invaluable sense and become more conscious of its myriad messages.
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Lisa is certified in 7 different areas of natural wellness and holds a degree in Transformational Psychology. She is the founder of Lifeshare University of Healing, LLC, and the Published Author of Nine Amethyst Angels Self Help Book and the Personal Development CD Series "A Life from Roses to Lilies, Back to Seed.