olfaction

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smell

 [smel]
the sense that enables one to perceive odors; it depends on the stimulation of sense organs in the nose by small particles carried in inhaled air. It is important not only for the detection of odors, but also for the enjoyment of food, since flavor is a blend of taste and smell. Taste registers only four qualities: salt, sour, bitter, and sweet; other qualities of flavor depend on smell. Called also olfaction.



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.

ol·fac·tion

(ol-fak'shŭn),
1. The sense of smell.
2. The act of smelling.
Synonym(s): osmesis, osphresis
[L. ol- facio, pp. -factus, to smell]

olfaction

(ŏl-făk′shən, ōl-)
n.
1. The sense of smell.
2. The act or process of smelling.

ol·fac·tion

(ōl-fak'shŭn)
1. The sense of smell.
Synonym(s): smell (2) .
2. The act of smelling.
Synonym(s): osphresis.
[L. ol-facio, pp. -factus, to smell]

olfaction

The sense of smell or the act of smelling.

olfaction

the sense of smell, in which there is chemoreception of molecules suspended in the air.

ol·fac·tion

(ōl-fak'shŭn)
1. Sense of smell.
2. Act of smelling.
[L. ol-facio, pp. -factus, to smell]

Patient discussion about olfaction

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?

A. I can't remember where I heard about the chiropractor's involvement but it is really unpleasant. I tend to make life unpleasant for others to, just not to have a migraine. Things like cooking popcorn, perfumes, trash and many other things will give me a migraine (not a headache) right away. It may be called Hyperosmia (abnormal sense of smell).

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

A. HI betty,thank god he has a friend like you--I dont like saying this but,your friend is killing himself,and the sooner you try to get him into a hospital the better--it not going to be easy-but you can only try.At this point he is at risk of LUNG CANCER--A VERY BAD INFECTION--AND CARDIAC ARREST,because of his weight,eating is an addiction,and people die from it,also people die from respiratory arrest because of his weight--stay strong--mrfoot56

More discussions about olfaction
References in periodicals archive ?
The good news here is that losing your sense of smell for the time being tells you the concussion that hit you isn't to be dismissed.
Within 24 hours of their injury, just over half of the patients with mild concussions had a reduced sense of smell, compared with 5% of the patients with broken bones, the Canadian researchers found.
The National Institute on Aging says that, as a person gets older, his or her sense of smell may fade, and that will also affect taste.
It's long been known that people who suffer a major concussion can lose their sense of smell temporarily and also develop effective problems, such as anxiety and depression.
The sense of smell is known to deteriorate with age, but researchers have previously found it might also indicate health problems and deteriorating health before it is recognised by doctors.
The reason for this is that scientists have shown that a reduction in the sense of smell might be an early sign of both Alzheimer's and Parkinson's.
Touch feels different depending on the situation as it's not just processed as a PREGNANT Sense of smell heightened physical sensation - it's also put in a social and emotional context.
'But what I can tell you is I've saved myself twice from fire owing to my sense of smell. Once while going to bed, I smelt electrical burn.
Several times now I've written about the keenness of a dog's sense of smell and how it can diagnose serious illnesses.
According to the Observer, Mrs Henderson had no sense of smell and did not know a flame had gone out under the gas wash boiler in the kitchenette.
"Salmon are known for utilising their sense of smell for essential activities, from navigation and finding food, to detecting predators and reproducing.
Adiminished sense of smell could be a symptom of something as harmless as a seasonal allergy, or it could be a sign of a heightened dementia risk.