Konka - Meatus

Endrianus Jaya Putra

In 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 nose.

Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in vertebrates.

Turbinates are composed of pseudostratified columnar, ciliated respiratory epithelium with a thick, vascular and erectile glandular tissue layer. The turbinates are located laterally in the nasal cavities, curling medially and downwards into the nasal airway

All three turbinates are innervated by pain and temperature receptors, via the trigeminal nerve.

• The inferior turbinates are the largest turbinates, and can be as long as the index finger in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.

• The middle turbinates are smaller. In humans, they are usually as long as the little finger. They project downwards over the openings of the maxillary 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 turbinates are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the olfactory bulb.

Role of turbinates in the respiratory system

• The turbinates compose most of the mucosal tissue of the nose and are required for functional respiration.

• The turbinates are also responsible for filtration, heating and humidification of air inhaled through the nose. – filtration is mostly achieved by other more effective means such

as mucous and cilla. As air passes over the turbinate tissues it is heated to body temperature, humidified (up to 98% water saturation) and filtered.

– 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 congestion and decongestion, in response to the climatic conditions and changing needs of the body.

Role of turbinates as an immunological defense

• The respiratory epithelium which covers the erectile tissue (or lamina propria) of the turbinates plays a major role in the body’s first line of immunological defense.

• The respiratory epithelium is partially composed of mucus-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 system which protects the body from being infected by viruses or bacteria.

Role of turbinates in olfaction

• 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 anosmia.

• The turbinates also increase the surface area 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.

Normal-sized right inferior turbinate with a moderate inferior septal deflection.

Mucosal hypertrophy of the right inferior turbinate with total airway obstruction.

Longstanding rhinolith leading to anatomical alterations of the ipsilateral inferior nasal meatus

and turbinate

swollen turbinates with thick secretionsIn alergic rhinitis patient

pale turbinates and dry secretions in smoker

large right concha bullosa.

Nasal Meatus

• The superior meatus, the smallest of the three meatuses of the nose, occupies the middle third of the lateral wall of the nasal cavity. It lies between the superior nasal conchae and middle nasal conchae; the sphenopalatine foramen opens into it behind, and the posterior ethmoidal cells in front.

• The middle meatus is a nasal opening or canal situated between the middle and inferior conchae, and extends from the anterior to the posterior end of the latter.

• The inferior meatus, the largest of the three meatuses of the nose, is the space between the inferior concha and the floor of the nasal cavity.

• The term serous fluid is used for various bodily fluids that are typically pale yellow and transparent, and of a benign nature, that fill the inside of body cavities.

• Serous fluid originates from serous glands, with secretions enriched with proteins and water. Serous fluid may also originate from mixed glands, which contain both mucous and serous cells. A common trait of serous fluids is their role in assisting digestion, excretion, and respiration.

• Mucous fluid may also originate from mixed glands, which contain both serous and mucous cells. It is a viscous colloid containing antiseptic enzymes (such as lysozyme), proteins such as lactoferrin, glycoproteins known as mucins that are produced by goblet cells in the mucous membranes and submucosal glands, immunoglobulins, and inorganic salts.

• This mucus serves to protect epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems in mammals; the epidermis in amphibians; and the gills in fish. A major function of this mucus is to protect against infectious agents such as fungi, bacteria and viruses. The average human body produces about a litre of mucus per day.

• In the respiratory system mucus aids in the protection of the lungs by trapping foreign particles that enter it, particularly through the nose, during normal breathing. "Phlegm" is a specialized term for mucus that is restricted to the respiratory tract, while the term "mucus" more globally describes secretions of the nasal passages.

• Nasal mucus is produced by the nasal mucosa, and mucal tissues lining the airways (trachea, bronchus, bronchioles) is produced by specialized airway epithelial cells (goblet cells) and submucosal glands. Small particles such as dust, particulate pollutants, and allergens as well as infectious agents such as bacteria are caught in the viscous nasal or airway mucus and prevented from entering the system. This event along with the continual movement of the respiratory mucus layer toward the oropharynx, helps prevent foreign objects from entering the lungs during breathing. Additionally, mucus aids in moisturizing the inhaled air and prevents tissues such as the nasal and airway epithelia from drying out. Nasal and airway mucus is produced continuously, with most of it swallowed unconsciously, even when it is dried.