Aromatherapy and the Olfactory System

AROMATHERAPY AND THE IMPORTANCE OF THE RELATIONSHIP WITH THE OLFACTORY SYSTEM

The sense of smell is the most basic and primitive of all our senses, and is of vital importance to humans since it has helped with the survival of our species. For our prehistoric ancestors, smell was equally important in the battle for survival, since certain odours such as smoke and rotting flesh would often signal danger.

Without the sense of smell, humans would not have survived the evolutionary process!

Nowadays however, we perceive things mainly through our eyes and ears, and in fact the sense of smell is now repressed and controlled in a way that nature never intended. Just think about the way we try to mask any smells in daily life that we feel are unpleasant and unsociable by using deodorants and air-fresheners. Smell is important to our well-being, except now we seem to have become tolerant to only pleasant odours.

Aromatherapy is a perfect example of this. Aromatherapy is the use of fragrance to enhance health and promote feelings of well-being. Although a particular essential oil may be precisely what is required to treat a physical condition, a client may object during a treatment if they do not like the aroma of the oil.

The olfactory system includes all physical organs or cells relating or contributing to, the sense of smell. When we inhale through the nose, airborne molecules interact with the olfactory organs and, almost immediately, the brain.

Molecules inhaled through the nose or mouth are also carried to the lungs and interact with the respiratory system. Thus, inhaled essential oils can affect the body in several ways.

The knowledge that smells can have a powerful effect on the mind has been known since ancient times!

Have you ever wondered how the nose distinguishes between the delicious aroma of cooking food and the danger signals of something burning? The process of smelling is called olfaction and is incredibly complicated, taking place in several areas of the brain including the limbic system. The limbic system is linked to the perception of odour, sensations of pleasure and pain, emotions like rage, fear, sadness and sexual feelings.

When we sniff to distinguish a particular odour, molecules emitting from the substance travel through the air and enter the nose. There are 50 million smell receptors located at the top of the nasal cavity occupying an area the size of a postage stamp. These slender nerve receptors are called ‘cilia’ and are connected to an organ called the olfactory bulb (bulbus olfactorius), which in turn is connected directly to the brain.

When an odour molecule has penetrated into the receptor there is an effect on the nerve cell belonging to this cilium. This nerve now sends a signal to the olfactory bulb which is a major structure in the limbic system and is where the olfactory impressions are first processed. Nerve cell responses are then sent in the olfactory stalk to the limbic system. These receptor cells are, an extension of the brain into the outside world!

Research has established that essential oils have an influence on the Limbic System in the brain which brings about changes in the brains chemistry, and can influence our emotions. Precisely which emotion is evoked when experiencing a fragrance will of course depend on the natural chemistry of the particular oil concerned.

Scientists now believe that all our emotions are the result of neurochemicals such as noradrenaline and serotonin being released into the bloodstream, and mood swings are thought to be a result of these influences, particularly when they are in the extreme. Given these facts it’s not hard to see how essential oils can help balance and influence our moods.

For example, when you smell lemon oil, some molecules dissolve in the mucus lining of the olfactory epithelium on the roof of the nasal cavity. There, the molecules stimulate olfactory receptors. Olfactory sensory neurons carry the signals from the receptors to the olfactory bulb, which filters and begins processing the input signals of the lemon scent. Mitral cells then carry the output signals from the olfactory bulb to the olfactory cortex, which allows you to perceive and recognize the tangy scent of lemon. This link explains why smells are often linked to specific memories. For example, if you have had a positive experience with lemon meringue pie, the scent of lemon may induce positive thoughts.

Your nose has two functions; to filter and warm the air that you breathe in, and to act as the first part of the olfactory system (your sense of smell). Your lungs have a HUGE surface area that is intimately connected to your blood system, and when directly inhaled, substances can enter straight into your blood stream, including essential oils! This makes essential oils great at treating bronchial issues such as a cough or chest infections.

Olfaction is one of the most primal senses in the human brain. Smell is a chemical reaction that happens when receptors in your brain interact with the chemicals that make up what you just smelled.

During inhalation, odour molecules travel through the nose and affect the brain through a variety of receptor sites, one of which is the limbic system, which is commonly referred to as the “emotional brain.”

The limbic system is directly connected to those parts of the brain that control heart rate, blood pressure, breathing, memory, stress levels, and hormone balance. This relationship helps explain why smells often trigger emotions. Knowing this, we can hypothesise how inhalation of essential oils can have some profound physiological and psychological effects!

When it comes to essential oils, their powerfully fragrant aromas are the first thing we notice as we open the bottle. By definition, essential oils are a rich mixture of volatile aromatic compounds. Because of their volatility, aroma is actually an intrinsic feature to essential oils, or in other words, essential oils are their aroma. Aroma in a “chemical” sense means that individual compounds (in this case, essential oil constituents) are able to interact with olfactory receptors in the nose. Not every type of compound elicits an aroma, because the compounds have to be very small and readily evaporate into the air. Essential oil compounds meet both of these criteria and are able to quickly and easily bind to smell receptors in the nose. The chemistry of essential oils varies widely from oil to oil, which explains why essential oils possess such widely different aromas, and affect us in different ways.

One of the most well-studied areas of aroma research is the effect of smell on emotions and mood. For example, there is convincing evidence demonstrating that simply inhaling the aroma of an essential oil is effective for calming nervous or anxious feelings in a variety of settings. The smell receptors located on the upper surface of the nasal cavity make direct links with the limbic system of the brain, an area that governs the body’s emotional responses. This close connection between aroma and emotion becomes obvious in our everyday life as certain odours trigger memories or specific feelings. Some aromas directly impact mood (for example calming, balancing, or invigorating), while others trigger memories of a specific experience, often one tied to a strong emotion.

In conclusion, the results of many studies indicate that essential oils do have the ability to help reduce stress levels, but only if certain conditions are met. Aromatherapy is only effective if the essential oils used are suited to the individual benefiting from them. A negative emotional or physical reaction will contribute to stress, as opposed to relieving it. Similarly, the method in which the essential oils are applied can affect the desired outcomes. If a person is not comfortable with the method, it can ultimately increase the stress level.

Aromatherapy has a very wide scope description to it that doesn’t necessarily cover what essential oils are capable of. Essential oils are able to work in many different ways to help the body.

Through the skin – Topical application is a very common method of use for essential oils. While topical application is great for skin conditions or acute issues, it is the slowest and most diluted way to get them into your bloodstream. How fast they enter the bloodstream is dependent on the thickness of the skin they are being applied to and how diluted they are with a carrier.

Through the nose – The fastest method of getting essential oils into the body, inhalation is one of the most effective and popular ways to use essential oils. Made up of a combination of chemical constituents, when inhaled these constituents travel to either your brain, your lungs or both! Essential oils can be used in a variety of ways and for a variety of reasons, through inhalation. Inhalation is commonly used for respiratory tract infections, allergies, headaches, asthma, prevention of illness, depression, fatigue, nausea, insomnia, nicotine withdrawal, and even PTSD.

There is no question that effect of massage taking into account the olfactory process and the use of essential oils provides a powerful mechanism for health and well-being!