Odors accompany people, even more than taste, for a lifetime. Odors not only convey information, they also influence emotions. Pleasant and unpleasant scents and taste warn people, trigger well-being or convey enjoyment. Every year around 50, 000 people in Germany suffer from disorders of the sense of smell and taste - such as sinusitis or Parkinson's disease. Even a simple cold can significantly affect the sensation.
Interplay of smell and taste
The scent of freshly ground coffee, fresh bread, bread rolls or cookies at Christmas time awakens feelings and memories in every person and "makes your mouth water". But with your tongue, food and drinks taste bland, and the food is not fun, if you can not smell it. Taste and smell must work together so that a harmonious whole comes out of it.
How the sensory cells work with smelling and tasting
The sense of smell and taste are chemical senses: it is the invisible molecules of the starting materials that reach the olfactory mucosa via the mouth and nose. Salty or sweet, sour or bitter - only these four flavors recognize the tongue with the help of their taste buds. There are special cell networks, so-called receptors, which transmit the perceived taste to the brain.
By means of the nose, however, one can distinguish thousands of smells. The olfactory cells, also called "olfactory sensory cells, " are activated by odors. Almost all of these nerve cells are located in a small area in the roof of the nasal cavity, the olfactory epithelium. Here are millions of olfactory cells. From there, the signals are transmitted via the olfactory nerve directly to the brain.
An important role in the interplay of smell and taste plays the trigeminal nerve, the sensory nerve: This cranial nerve, which splits into three branches that extend to the eye, upper and lower jaw, conveys sensations such as the burning of chili or the cooling effect of menthol.
Diseases and diagnosis
"Hyposmia" medicine calls a disease in which the smelling ability has been partially lost. "Anosmia" is the technical term for the complete destruction of the sense of smell. A common cause of a temporary loss of smell and taste is in most cases a cold. Here it is swelling of the nasal mucosa, which leads to impairment of the sense of smell.
Influenza viruses also colonize the mucous membranes and can temporarily disturb the epithelium of the olfactory mucosa. Likewise, nasal polyps affect the sensation of smell. The sensory perceptions return after the disease subsides.
To find out the cause of the disease, the doctor examines the nose, the nasal mucosa and the nasopharynx. Then he checks separately on both sides of the sense of smell and doing it also a taste test. An examination of the patency of the nose and an allergy test are also required to rule out an allergy. If necessary, the paranasal sinuses are examined with the help of X-rays or computed tomography.
Olfactory disorders in Alzheimer's and Parkinson's
If there is no cold, the doctor will check if there are central olfactory disorders in the brain, for example diabetes, hypertension, malnutrition or malnutrition. Even some medications can disturb the sense of smell and taste. Research has shown that in about 80 percent of all Parkinson's and Alzheimer's patients, olfactory disturbances occur at an early stage. The causes of the odor disorders in both diseases are not in disturbed olfactory sensory cells, but directly in the brain.
From around the age of 65, the ability to regenerate the olfactory cells decreases. The perception of taste is also formed, if not so strong, back. Therefore, many older people spice their food too much and prefer desserts. From the age of 80, 80 percent of the population suffer from disturbances of smell and taste. For smokers and people who, for example, work a lot with strong-smelling chemicals in their jobs, the sense of smell is limited.