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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.


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


/ol·fac·tion/ (ol-fak´shun)
1. smell; the ability to perceive and distinguish odors.
2. the act of perceiving and distinguishing odors.


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


Etymology: L, olfacere, to smell
1 the act of smelling.
2 the sense of smell. olfactory, adj.


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


The sense of smell or the act of smelling.


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

olfaction (ōlˑ·fakˈ·shn),

n the sense of smell.


1. Sense of smell.
2. Act of smelling.
[L. ol-facio, pp. -factus, to smell]

olfaction (olfak´shən),

n the process of sensing certain odors during basic patient assessment, both intraoral and extraoral, in order to note changes in disease states; simply by detecting certain odors, the dental professional can suspect periodontitis, dental caries, necrotizing periodontal disease, diabetic acidosis, cigarette use, and alcohol abuse.


1. the act of smelling.
2. the sense of 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 ?
This year I'm aiming for something to host my olfactory senses.
The perfumier story is particularly engaging, intertwining a tale of the harsh realities of mental illness with rich, evocative language that draws on the olfactory senses and is reminiscent of Patrick Suskind's Perfume novel.
SOUTH ASIAN fiction is expected to be rich; full of mangoes and spices, colour and emotions -- engaging taste buds and olfactory senses as much as your intellect, like the local argument that eating with your fingers helps involve five senses.
Yet another Canadian with heightened olfactory senses wrote: "Everyone I asked who's smelt the bills agree they smell like maple.
As an example of a poorly designed experiment, Shodell (2010) describes and analyzes experiments by scientists of the 1660s who were attempting to discover, by their olfactory senses, whether glass and crystal could be penetrated by pungent odors such as that of horse urine.
She examines in turn, the scents frankincense, rose, sassafras, rosemary, ambergris, and jasmine, noting their manner of use, cultural and religious roles, economic properties, and what their use can tell us about the way our olfactory senses have shaped our interactions with one another and our environment.
If you aren't experiencing any symptoms of MCI or are having other signs of mental or physical problems, I wouldn't assume that changes in your olfactory senses are anything other than some unavoidable aspects of aging.
BOTANICAL GARDENS, BIRMINGHAM Entering the glasshouses my olfactory senses Were caressed with bewildering aromas, like myriad Perfumes sprayed from generous bottles.
3) Duck hunters need not launder their hunting attire or their bodies three times a day to avoid alerting the olfactory senses of their quarry.
That doesn't pass the smell test, even for people of weak olfactory senses.
According to Debenhams the north south divide even extends to our olfactory senses, with perfume preferences differing depending on which side of the Watford Gap you are on.
So, it can catch the poachers with his powerful sight and olfactory senses," said C L Arya, Range Officer, Haldwani Forest Division.