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The organs of smell are small patches of special cells (olfactory cells) in the nasal mucosa. One patch is located in each of the two main compartments of the back of the nose. The olfactory cells are connected to the brain by the first cranial nerve (olfactory nerve). Air currents do not flow directly over the patches in breathing; this is why one must sniff to detect a faint odor or to enjoy a fragrance to the fullest.
When one sniffs, air currents carrying molecules of odorous chemicals enter special compartments, called olfactory chambers, where the chemicals are dissolved in mucus. There they can act on the organs of smell in much the same way that solutions act on the taste buds of the tongue. The endings of the sensory nerves that detect odors, the olfactory receptors, can quickly adapt to an odor and cease to be stimulated by it after a few minutes of full exposure.
The sense of smell may be diminished or lost entirely, usually temporarily, as a result of an obstruction of the nose, nasal infection, injury or deterioration of the nasal tissue, brain tumor, or mental illness. In rare instances, injury or disease causes such damage to the olfactory nerve that loss of the sense of smell is permanent. Complete absence of the sense of smell is known as anosmia.
verb To perceive odour or scent via the olfactory nerve
smellnoun Popularly, an odor or scent verb To perceive odor or scent by stimuli affecting the olfactory nerves. See Olfaction.
smell(smel) [ME. smellen, to reek]
Abnormalities in the sense of smell include: Anosmia: A loss of the sense of smell. It may be a local and temporary condition resulting from acute and chronic rhinitis, mouth breathing, nasal polyps, dryness of the nasal mucous membrane, pollens, or very offensive odors. It may also result from disease or injury of the olfactory tract, bone disease near the olfactory nerve, disease of the nasal accessory sinuses, meningitis, or tumors or syphilis affecting the olfactory nerve. It may rarely represent a conversion disorder. Disease of one cranial hemisphere or of one nasal chamber may also account for anosmia. Synonym: anodmia; anosphrasia
Hyperosmia: An increased sensitivity to odors.
Kakosmia: The perception of bad odors where none exist; it may be due to head injuries or occur in hallucinations or certain psychoses. Synonym: cacosmia
Parosmia: A perverted sense of smell. Odors that are considered agreeable by others are perceived as being offensive, and disagreeable odors are found pleasant. Synonym: parosphresia
smellOne of the five senses. Smell is mediated by airborne chemical particles that dissolve in the layer of mucus on the upper part of the nose lining and stimulate the endings of the olfactory nerve twigs. The olfactory system is capable of distinguishing a large number of distinct odours.
Patient discussion about smell
Q. I have a very acute sense of smell. Most things that have a smell cause me to have Migraines every day. I have heard that a chiropractor is who I need to treat me for this problem. Anyone else here have this problem? What have you done and were you able to treat it?
Q. MY friends body is leaking and he smells awful. He also has a skin rash. He stinks.Can I help him.He is big. smokes too much,and does shower but he still smells. I need to get him in a chairty hospital. If ignored what will happened. Thank You Bettye