The human nose includes the outer nose, the inner nose, the paranasal sinuses and the numerous pathways of the anatomical structure. The nose is functionally part of the upper airways and is thus involved in the pulmonary respiration, with which the alveoli of the lungs supply the individual body tissues with vital oxygen.
Behind the nasal cavity lies the pharynx, into which the trachea opens. At the level of the fourth and fifth thoracic vertebra, the trachea runs into the two main bronchi. In addition to the perception of smell, the nose has a correspondingly important importance in breathing.
The nose regulates the respiratory flow, does the rough cleaning of the breathing air and conditions the inhaled air. This conditioning corresponds to an adaptation of temperatures and humidities. The nasal mucosa makes this conditioning of the breath. If necessary, the air stream is heated and moistened on the mucosal surfaces. Then it flows further in the direction of the pharynx. In this way, the respiratory air is given an ideal temperature and humidity in order to be processed in the biological environment of the human organism.
The lung respiration occurs in humans either over the mouth or the nose. The nasal turbinates are fake cavernous and can significantly change their size. As long as the nose is not clogged or otherwise impaired, it primarily serves human pulmonary respiration. Up to 10 000 liters of air inhale the nose every day.
Nasal breathing takes place unevenly in a person in physical rest. Both nostrils are alternately used for breathing. This process corresponds to the so-called nasal cycle. The inhaled airflow is reduced in each case one of the nostrils and thus allows a regeneration of the mucosa in the corresponding nostril. The main stream changes after the regeneration of one nostril ever unnoticed to the other nostril.
The nose serves both inhalation and exhalation of breathing air. Each airflow undergoes conditioning during nasal breathing. Extremely cold air, for example, is warmed and moistened on the surface of the warm nasal mucous membrane. The mucous membrane cools down and dries out to a certain extent. But exhaling gives it back most of its heat and moisture.
The conditioning of the breathing air corresponds to an air conditioning of the inhaled air on the climatic conditions of the Lungenveveolen. Thus, the nasal mucosa maintains the undisturbed function of the bronchioalveolar mucous membranes. Especially in extreme climatic conditions, this process is imperative in the long run.
Some authors also consider the purification of the air flow under the nasal conditioning of the air. As a connecting link between the ambient air and the lower respiratory tract, the nose is a first barrier to foreign substances and particles. The nasal hairs catch coarse particles and the nasal secretion filters finer foreign substances from the breathing air. The persistent movement of the cilia carries the nasal secretions permanently towards the pharynx. Excessive secretions, together with the filtered foreign particles, are transported outwards by sneezing.
In the narrow as well as the expanded meaning, the conditioning of the respiratory air in the nose ensures an approximate ideal of pulmonary respiration and is superior to respiration through the mouth in numerous ways.
The conditioning of the air is disturbed in many mucous membrane diseases. If the nose is too dry, for example, the humidity of the inspired airflow can no longer easily be adapted to the climatic conditions of the alveoli.
A dry nose may be present as a result of dry runny nose, rhinitis sicca or atrophic rhinopathy. The nasal mucosa dries out. Mostly the reason is the beginning of a cold. Even dry air or extreme dust pollution, however, can dry out the nasal mucous membranes. In extreme cases, different bacteria settle on the dry nasal mucosa.
In addition to a feeling of dryness in the nose, there are often itching or a slight burning sensation in this phenomenon. The nasal breathing is then limited because crusts, scabs or barking form. Nosebleeds and limited smelling ability can also be caused by a dry nose.
The moistening of the inhaled air does not succeed a dry nose, which explains the crusting, scab and Borkenbildung in the nose. The infection susceptibility of those affected increases as a result. In principle, the conditioning of the breathing air in all diseases of the inner nose can be difficult.
The main symptom of such diseases is always a nasal obstruction. The causes may be from bends, spur formations, enlarged nasal conchae, enlarged tonsils, occlusion of the posterior nasal cavity, nasal polyps or other neoplasms of the nose.
Rhinitis is also a common disease phenomenon. It is an inflammation of the nasal mucosa. For example, acute rhinitis is associated with runny nose and is usually caused by one of 100 subtypes of rhinoviruses. In addition to shivering and fatigue or head pressure rhinitis is initially a dry nose. Later, the formation of a water-clear secretion, which in turn becomes a mucous-purulent secretion.
Exactly like the dryness of the nose, increased nasal secretion impedes the conditioning of the breathing air. An exaggerated nasal secretion, however, does not necessarily have to be due to rhinoviruses, but may also be due to nasal hyperreactivity.