Sense of smell

Smell is the ability to perceive the smells. This ability is carried out by means of the olfactory analyzer, peripheral whose Department (receptor) are specific nerve cells located in the mucous membrane of the upper and middle part of the nasal passages.
Irritant olfactory analyzer are molecules odorous substances that enter the olfactory region or by inhalation through the nose, especially when the forced inhalation (nochange), or from the nasopharynx at the time of ingestion of food; in the latter case, olfactory sensation combined with gustatory (taste, smell). Man has a different degree of smell to various odorous substances. Sensitivity to certain substances particularly high. So, for example, ethyl mercaptan causes olfactory sensation when keeping it in the quantity 0,00019 mg in 1 liter of air.
Decline and loss of smell often arise in inflammatory and atrophic processes in mucous membrane of the nose. In some cases, impaired sense of smell is one of the major symptoms of Central nervous system.
To study the sharpness of smell are set odorous substances such composition: 1) 0,5% solution of acetic acid (smell), 2) wine alcohol (smell medium strength), 3) simple Valerian tincture (strong smell), 4) turpentine (very strong smell). For a more precise definition of sharpness of smell using special devices - olfactometry - various designs. These devices make it possible to determine the minimum concentration of odorous substances when the olfactory sense.