Fragrance of Essential Oils
How Fragrance is Created
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Plants convert hydrogen, carbon and oxygen into glucose.
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Plants use minerals and nitrogen, with the help of enzymes, to convert glucose into amino acids.
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Amino acids convert to protein.
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Constituents with different chemical structures generate different odours.
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Mustard Oil - Allyl isothiocyanate
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Garlic Oil - Allyl sulfides
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Jasmine - Anthranilates
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Orange Blossom - Indole
Important of the Amygdala
In 1989 researchers realised the importance of the amygdala, the amygdala is the part of the brain that stores and releases emotional trauma.
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How Fragrance is Registered by the Brain
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There are two theories about scent: "lock and key" and "vibrational".
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Lock and Key suggests that as molecules within a fragrance flash into the air, they stimulate the door receptors of the olfactory system.
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These receptors are similar to hair-like extensions of the nerve fibres that lie submerged in a thin layer of mucous.
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As the vapour molecules enter the nasal cavity, they are received by the receptors - similar to a key in a lock.
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If a vapour has the proper structure (or vibration as some say), it is received by the nerve endings in the form of an impulse.
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The nerve impulse is then transmitted to the limbic system.
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The primary structures within the limbic system include the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus. The amygdala is the emotion centre of the brain, while the hippocampus plays an essential role in the formation of new memories about past experiences.
As the limbic system is directly connected to those parts of the brain that control the heart rate, blood pressure, breathing, memory, stress levels, and hormone balance, essential oils can have profound physiological and psychological effects.
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The sense of smell is the only one of the five senses directly linked to the limbic lobe of the brain, the emotional control centre.
Anxiety, depression, fear, anger and joy all emanate from this region, all the other senses are routed through the hypothalamus.
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A powerful aroma will evoke emotion long before there is conscious thought.
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