The nose warms the air we breathe and gives the inhaled airflow a certain humidity to adapt it to the climatic conditions of the alveoli. This process is called conditioning the air we breathe and is the main function of the nasal mucosa. In rhinitis (common cold), conditioning of the air we breathe is more difficult.
What is conditioning of the air we breathe?
The nose regulates respiratory flow, does the gross cleaning of the air we breathe, and conditions the air we breathe. This conditioning corresponds to an adjustment of temperatures and humidities. The human nose includes the external nose, the internal nose, the paranasal sinuses and the numerous conduits of the anatomical structure. Functionally, the nose is one of the upper respiratory tracts and thus participates in pulmonary respiration, by which the alveoli of the lungs supply vital oxygen to the individual tissues of the body. Behind the nasal cavity lies the pharynx, into which the trachea opens. At the level of the fourth and fifth thoracic vertebrae, the trachea runs into the two main bronchi. In addition to the perception of smell, the nose thus plays a correspondingly important role in breathing. The nose regulates the respiratory flow, takes care of the coarse cleaning of the respiratory air and conditions the inhaled air. This conditioning corresponds to an adjustment of temperatures and humidities. The nasal mucosa performs this conditioning of the inhaled air. On the mucosal surfaces, the airflow is warmed and humidified, if necessary. It then flows further in the direction of the pharynx. In this way, the breathing air is given an ideal temperature and humidity to be processed in the biological milieu of the human organism.
Function and task
Pulmonary respiration in humans occurs either through the mouth or the nose. The turbinates are faux swellings and can change size significantly. As long as the nose is not obstructed or otherwise impaired, its primary function is human pulmonary breathing. The nose inhales up to 10,000 liters of air daily. Nasal breathing occurs unevenly in a person at physical rest. Both nostrils are used alternately for breathing. This process corresponds to the so-called nasal cycle. The inhaled air flow is reduced in one of the nostrils at a time, allowing regeneration of the mucous membrane in the corresponding nostril. After the regeneration of one nostril, the main flow changes to the other nostril, each unnoticed. The nose serves both for inhalation and exhalation of breathable air. Each air stream undergoes conditioning during nasal breathing. Extremely cold air, for example, is warmed and moistened on the surface of the warm nasal mucosa. In the process, the mucosa cools and dries out to a certain degree. When it exhales, however, it regains most of its warmth and moisture. The conditioning of the respiratory air thus corresponds to a climatization of the inhaled air to the climatic conditions of the pulmonary alveoli. Thus, the nasal mucosa maintains the unimpaired function of the bronchioalveolar mucosa. Especially in extreme climatic conditions, this process is mandatory in the long run. Some authors also include the purification of the airflow under the nasal conditioning of the respiratory air. As the connecting tract between the ambient air and the lower respiratory tract, the nose is a first barrier to foreign substances and particles. Nasal hairs intercept coarse particles and nasal secretions filter finer foreign substances from the air we breathe. The continuous movement of the cilia permanently transports the nasal secretion towards the pharynx. Excess secretion is transported to the outside together with the filtered foreign particles as the person sneezes. In the narrow, as well as the extended meaning, conditioning of breathing air in the nose ensures an approximate ideal of lung breathing and is superior to breathing through the mouth in numerous ways.
Diseases and ailments
The conditioning of the respiratory air is disturbed in many mucosal diseases. For example, in an excessively dry nose, the humidity of the inhaled airflow can no longer be readily adjusted to the climatic conditions of the alveoli. A dry nose can be present in the context of dry rhinitis, rhinitis sicca or atrophic rhinopathy. In this case, the nasal mucosa dries out. Most often, the cause is the beginning of a cold rhinitis.However, dry room air or extreme dust exposure can also dry out the nasal mucous membranes. In extreme cases, various bacteria settle on the dry nasal mucosa. In addition to a feeling of dryness in the nose, this phenomenon is often accompanied by itching or a slight burning sensation. Nasal breathing is then restricted as crusts, scabs or bark form. Nosebleeds and limited ability to smell can also be caused by a dry nose. A dry nose no longer succeeds in moistening the inhaled air, which explains the formation of crusts, scabs and bark in the nose. The susceptibility to infections of those affected increases as a result. Basically, the conditioning of the breathing air can be impeded in all diseases of the internal nose. The leading symptom of such diseases is always obstructed nasal breathing. The causes can range from bent nostrils, spur formation, enlarged turbinates, enlarged adenoids, obstruction of the posterior nasal opening, nasal polyps or other tumors of the nose. Rhinitis is also a common disease phenomenon. It is an inflammation of the nasal mucosa. Acute rhinitis is present, for example, in rhinitis and is usually caused by one of 100 subtypes of rhinoviruses. In addition to chills and fatigue or head pressure, rhinitis initially presents with a dry nose. Later, there is the formation of a watery clear secretion, which in turn becomes a mucopurulent secretion. Just like nasal dryness, increased nasal secretion also hinders the conditioning of the air we breathe. However, excessive nasal secretion does not necessarily have to be due to rhinoviruses; it can also be due to nasal hyperreactivity.
