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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 ?
Therefore, we believe that septoplasty and nasal septum correction appear to be beneficial for olfaction in type 3 SD.
Averaged characteristic attributes of Rieslings from Alsace, the Pfalz, Rheingau, Washington State and the Finger Lakes evaluated by a consumer panel for A) orthonasal olfaction and B) retronasal olfaction.
As the maxillary palps are involved in both olfaction and gustation, it is possible that some of the receptors expressed in these organs have a gustatory function.
The scratch-and-sniff test asks subjects to identify 40 odors and ranks olfaction as normal or mildly, moderately, or severely impaired.
Dstl conducts research studies into canine behaviour, olfaction and performance in support of the UK Ministry of Defence.
The aim of this retrospective study is to identify patients referred to a movement disorders clinic and clinician's private rooms who underwent initial evaluation of olfaction (using Sniffin Sticks smell discrimination testing) in addition to routine initial evaluation for motor Parkinsonism and other nonmotor symptoms and compared to the final diagnosis after longitudinal clinical follow-up according to standard criteria.
Forst makes use of sound to achieve this effect; Wolken (Clouds), 2010, engages olfaction to define the work's contours.
Part One, 'Scent: A Pan-Dimensional Perspective', deals with the sense of smell and the processes of olfaction, smell and the psyche, scented smoke and vapours, perfumes through the ages, and the psychology and sociology of fragrance.
Major finding: Global outcomes as measured by the Glasgow Outcome Scale-Extended were "essentially indistinguishable" between blast-related and nonblast TBI, as were numerous neuropsychological abnormalities; neurobehavioral impairments; focal neurological deficits such as those affecting olfaction, gait, and limb ataxia; headache-related disability; PTSD and its components; depression; alcohol misuse; and sleep disturbances.
The iTQi evaluates every product within the framework of a sensory analysis report, which includes the criteria of olfaction, vision, taste, after taste and texture.
Canadian scientists set out to evaluate the ability of electronic nose technology, which mimics human olfaction, to discriminate between refined and whole wheat bread made with white or red wheat bran, based on their headspace volatiles.
They address anatomy and embryology, physiology, advances in understanding the pathophysiology of rhinosinusitis, immunology, genetics, investigations, imaging, clinical examination and differential diagnosis, outcome measures and measurement tools, and conditions such as facial pain, disorders related to olfaction, rhinitis and rhinosinusitis, and trauma.