In
anatomyAnatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy and plant anatomy...
, a
nasal concha (or
turbinate) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) which protrudes into the breathing passage of the
noseAnatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth....
. Turbinate bone refers to any of the scrolled spongy
boneBones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s of the
nasal passagesThe nasal cavity is a large fluid filled space above and behind the nose in the middle of the face.- Function :The nasal cavities conditions the air to be received by the areas of the respiratory tract and noses...
in vertebrates.
In humans, the turbinates divide the nasal airway into three groove-like air passages –and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate controlling tissue.
Turbinates are composed of
pseudostratifiedA pseudostratified epithelium is a type of epithelium that, though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia...
columnarColumnar epithelia are epithelial cells whose heights are at least four times their width. Columnar epithelia are divided into simple , and stratified .* Simple columnar epithelia* Stratified columnar epithelia...
, ciliated
respiratory epitheliumRespiratory epithelium is a type of epithelium found lining the respiratory tract, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by action of the mucociliary escalator.-...
with a thick,
vascularThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
and erectile glandular tissue layer.
The turbinates are located laterally in the nasal cavities, curling medially and downwards into the nasal airway.
In
anatomyAnatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy and plant anatomy...
, a
nasal concha (or
turbinate) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) which protrudes into the breathing passage of the
noseAnatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth....
. Turbinate bone refers to any of the scrolled spongy
boneBones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s of the
nasal passagesThe nasal cavity is a large fluid filled space above and behind the nose in the middle of the face.- Function :The nasal cavities conditions the air to be received by the areas of the respiratory tract and noses...
in vertebrates.
In humans, the turbinates divide the nasal airway into three groove-like air passages –and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate controlling tissue.
Structure and functions of turbinates
Turbinates are composed of
pseudostratifiedA pseudostratified epithelium is a type of epithelium that, though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia...
columnarColumnar epithelia are epithelial cells whose heights are at least four times their width. Columnar epithelia are divided into simple , and stratified .* Simple columnar epithelia* Stratified columnar epithelia...
, ciliated
respiratory epitheliumRespiratory epithelium is a type of epithelium found lining the respiratory tract, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by action of the mucociliary escalator.-...
with a thick,
vascularThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
and erectile glandular tissue layer.
The turbinates are located laterally in the nasal cavities, curling medially and downwards into the nasal airway. Each pair is composed of one turbinate in either side of the nasal cavity, divided by the
septumThe nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
.
The
inferior turbinatesThe inferior nasal concha is one of the turbinates in the nose. It extends horizontally along the lateral wall of the nasal cavity [Fig. 1] and consists of a lamina of spongy bone, curled upon itself like a scroll...
are the largest turbinates, and can be as long as the
index fingerThe index finger, , is the second finger of a human hand....
in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
The
middle turbinatesThe medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha....
are smaller. In humans, they are usually as long as the
little fingerThe little finger, often called the pinky in American English and pinkie in Scottish English , is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger.-Muscles:There are four muscles that control the little finger, three of which comprise a group...
. They project downwards over the openings of the
maxillaryMaxillary is something related to the maxilla bone. It may be:*Maxillary artery*Maxillary nerve*Maxillary prominence*Maxillary sinus...
and ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled airflow travels between the inferior turbinate and the middle turbinate.
The
superior turbinatesThe back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha.-External links:* - lateral - coronal...
are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the
olfactory bulbThe olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors.-Anatomy:In most vertebrates, the olfactory bulb is the most rostral part of the brain. In humans, however, the olfactory bulb is on the inferior side of the brain...
.
Role of turbinates in the respiratory system
The turbinates compose most of the mucosal tissue of the
noseAnatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth....
and are required for functional
respirationThe respiratory systems function is to allow gas exchange to all parts of the body. The space between the alveoli & the capillaries, the anatomy or structure of the exchange system, and the precise physiological uses of the exchanged gases vary depending on the organism...
. The turbinates are enriched with airflow pressure and temperature sensing nerve receptors (linked to the “trigeminal” nerve route, the fifth cranial nerve), allowing for tremendous erectile capabilities of
nasal congestionNasal congestion is the blockage of the nasal passages usually due to membranes lining the nose becoming swollen from inflamed blood vessels. It is also known as nasal blockage, nasal obstruction, blocked nose, runny nose, stuffy nose, or stuffed up nose.Nasal congestion has many causes and can...
and decongestion, in response to the climatic conditions and changing needs of the body.
The turbinates are also responsible for filtration, heating and humidification of air inhaled through the nose. Of these three, filtration is the most important reason to breathe through the nose. As air passes over the turbinate tissues it is heated to body temperature, humidified (up to 98%
water saturationThe dew point is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation point...
) and filtered.
Role of turbinates as an immunological defense
The
respiratory epitheliumRespiratory epithelium is a type of epithelium found lining the respiratory tract, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by action of the mucociliary escalator.-...
which covers the erectile tissue (or
lamina propriaThe lamina propria is a constituent of the moist linings known as mucous membranes or mucosa, which line various tubes in the body ....
) of the turbinates plays a major role in the body’s first line of immunological defense. The respiratory epithelium is partially composed of
mucusIn vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. It is a viscous colloid containing antiseptic enzymes and immunoglobulins that serves to protect epithelial cells in the respiratory,...
-producing goblet cells. This secreted mucus covers the nasal cavities, and serves as a filter, by trapping air-borne particles larger than 2 to 3 micrometers. The respiratory epithelium also serves as a means of access for the
lymphatic systemThe lymphatic system in vertebrates is a network of conduits that carry a clear fluid called lymph. It also includes the lymphoid tissue through which the lymph travels. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated with the...
which protects the body from being infected by viruses or bacteria.
Role of turbinates in olfactionOlfaction refers to the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
The turbinates provide, first and foremost, the humidity needed to preserve the delicate olfactory
epitheliumIn biology and medicine, an epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body. Many glands are also formed from epithelial tissue...
needed to keep the olfactory receptors healthy and alert. If the epithelial layer gets dry or irritated, it may cease to function. This is usually a temporary condition, but over time, may lead to chronic
anosmiaAnosmia is a lack of functioning olfaction, or in other words, an inability to perceive smells. It can be either temporary or permanent. A related term, hyposmia, refers to decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one...
. The turbinates also increase the
surface areaSurface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved then the definition of arc length of a curve. For polyhedra the surface area is the sum of the areas of its faces...
of the inside of the nose, and by directing and deflecting airflow across the maximum mucosal surface of the inner nose, they are able to propel the inspired air. This, coupled with the humidity and filtration provided by the turbinates, helps to carry more scent molecules towards the higher, and very narrow regions of the nasal airways, where olfaction nerve receptors are located.
The superior turbinates literally hood-over, and protect the nerve axons piercing through the
cribriform plateThe cribriform plate of the ethmoid bone is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities....
(a porous bone plate that separates the nose from the brain) into the nose. Some areas of the middle turbinates are also innervated by the olfactory bulb. All three turbinates are innervated by
painPhysical Pain is the unpleasant feeling common to a headache and a stubbed toe. It typically consists of negative affect and aversion, and has location, duration, intensity and a distinctive quality...
and temperature receptors, via the
trigeminal nerveThe trigeminal nerve is responsible for sensation in the face. Sensory information from the face and body is processed by parallel pathways in the central nervous system....
(or, the fifth cranial nerve). Research has shown that there is a strong connection between these nerve endings and activation of the olfactory receptors, but science has yet to fully explain this interaction.
Turbinate dysfunction
Large, swollen turbinates may lead to blockage of nasal breathing. Allergies, exposure to environmental
irritantIrritant may refer to:* Something that causes irritation.* Irritant , a psychedelic trance album* Irritant , a United Kingdom rock musical group* Irritant , a stimulus or agent which induces the state of irritation...
s, or a persistent
inflammationInflammation is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. Inflammation is not a...
within the sinuses, can lead to turbinate swelling. Deformity of the nasal
septumIn anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.- In human anatomy :* Interatrial septum, the wall of tissue that separates the left and right atria of the heart...
can also result in enlarged turbinates.
Treatment of the underlying allergy or irritant may reduce turbinate swelling. In cases that do not resolve, or for treatment of
deviated septumNasal septum deviation is a common physical disorder of the nose, involving a displacement of the nasal septum.-Causes:It is most frequently caused by impact trauma, such as by a blow to the face. It can also be a congenital disorder, caused by compression of the nose during childbirth...
, turbinate reduction surgery may be required. Bipolar radiofrequency ablation, a technique used for
coblation tonsillectomyCoblation is a method used by otolaryngologists, also known as ENT specialists, to perform tonsillectomy, adenoidectomy, and other surgical procedures, including turbinate reduction and the treatment of snoring. Unlike traditional electrocautery methods, Coblation methods use radiofrequency to...
, is also used for the treatment of swollen turbinates; reduction by the use of pure heat is equally effective. Generally, because the turbinates are essential for respiration, only small amounts of turbinate tissue should be removed. Extensive reduction of the inferior or middle turbinates can cause
empty nose syndromeEmpty nose syndrome , also known as “the wide nasal cavity syndrome”, is a term coined by Kern and Stenqvist to describe a rare and debilitating iatrogenic syndrome of chronic nasal physiological impairment following overzealous turbinate resections in the nose .The main symptoms they noticed were...
.
Concha bullosaConcha Bullosa is an abnormal pneumatization of the middle turbinate which may interfere with normal ventilation of sinus ostia and can result in recurrent sinusitis....
is an abnormal pneumatization of the middle turbinate which may interfere with normal ventilation of sinus ostia and can result in recurrent sinusitis.
See also
- Bone terminology
- Anatomical terms of location
Standard anatomical terms of location are employed in science which deal with the anatomy of animals to avoid ambiguities which might otherwise arise. They are not language-specific, and thus require no translation...
- Superior nasal concha
The back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha.-External links:* - lateral - coronal...
, middle nasal conchaThe medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha....
and inferior nasal concha
- Empty nose syndrome
Empty nose syndrome , also known as “the wide nasal cavity syndrome”, is a term coined by Kern and Stenqvist to describe a rare and debilitating iatrogenic syndrome of chronic nasal physiological impairment following overzealous turbinate resections in the nose .The main symptoms they noticed were...
- Concha bullosa
Concha Bullosa is an abnormal pneumatization of the middle turbinate which may interfere with normal ventilation of sinus ostia and can result in recurrent sinusitis....