nasal cavity. Physiology of the nose In the human nasal cavity,

It is impossible to live without air. Our whole life consists of rhythmic inhalations and exhalations. That is why life-giving oxygen enters the body. What happens to the air in the nasal cavity? Why is it important for a person to breathe correctly and freely?

Basic functions of the nose and nasal cavity

Nature has assigned 4 main functions to the human nose:

• Breath. The most important function, designed to ensure the supply of oxygen to the tissues.
• Smell. One of the senses that allows you to fully live, perceiving the smells of the world around you.
• Protection. What happens to the air in the nasal cavity? First of all, it is cleansed. All large impurities, such as dust, linger on the inner hairs, called cilia. Smaller particles settle on the nasal mucosa. In addition, a kind of disinfection occurs, since the nasal mucus neutralizes the bacteria that have entered with the air. And in the nasal cavity, the air warms up to the required temperature and is moistened. Warming the air in the nasal cavity avoids many problems and diseases.
• Acoustics. Sound is amplified in the nasal cavity. The resonator function facilitates the pronunciation of consonants.

Anatomy. External nose

The nose is considered the entrance to the upper respiratory tract. This body has three components:

• external nose;
• nasal cavity;
• accessory sinuses.

The external nose is called the bone-cartilaginous base, covered with muscle tissue and skin. The shape of the nose for each person is individual, but in general it is a figure close to an irregular trihedral pyramid. The nasal bones are paired, they are attached to the frontal bone, forming the back of the nose. The wings and tip are formed from cartilage. The musculocutaneous covering has a large number of capillaries, nerve fibers and sebaceous glands.

Clinical anatomy of the nose. nasal cavity

Let's start with clinical anatomy. That is, we determine the structure and position of the nose and its cavity. In addition, we will determine with which departments the body interacts. The previous section described the location and contact of the outer part of the organ with other parts of the skull. As for the nasal cavity, it is located between the oral cavity and the fossa of the skull. And on the sides are the eye sockets.

The nasal cavity is divided into 2 parts by a septum. Interaction with the external environment occurs through the nostrils, with the nasopharynx - through the choanae (internal nasal opening). On each side, the nasal cavity is surrounded by four paranasal sinuses.

Why You Shouldn't Breathe Through Your Mouth

Many people breathe through their mouths without understanding why they shouldn't. This is especially true for children. What happens to the air when you breathe? It first passes through the external nose and nasal cavity. Before allowing air to flow into the larynx, it warms the body and cleanses it during passage through the nose. Through the larynx, air enters the trachea and bronchi, then into the lungs. Pulmonary vesicles (alveoli) are filled with air received during inhalation, and give it to the blood through numerous capillaries. When breathing through the mouth, dust particles and other foreign matter enter directly into the lungs.

If children breathe through their mouths, they may underdevelop maxillary sinuses and narrow the nasal passages. In addition, this leads to improper growth of teeth, which begin to "crawl" on top of each other. Since the balance between the facial and jaw parts is disturbed, language difficulties begin.

Understanding what happens to the air in the nasal cavity, and how improper breathing affects a person, it is much easier to explain to children and adults why it is necessary to breathe through the nose and not through the mouth.

Diseases of the external nose

There are not many diseases of the external nose. It can be congenital anomalies in babies. Such as a lateral trunk (dysgenesis), that is, the appearance of an additional nostril. Underdevelopment of one half of the nose or nasal cartilage (hypogenesis) may occur. Common diseases of the external nose are injuries. These can be fractures of the nasal bones and even separation of the organ. With age, the external nose can be affected by rhinophyma. This disease is poorly understood, in the people it is called raspberry, wine or potato nose. The disease leads to an increase in the body and changes in its shape. More commonly seen in men.

Diseases of the nasal cavity

Disease of the external nose and nasal cavity can be congenital or acquired. Congenital, for example, is the narrowness of the nasal passages. Narrowing can be partial or complete. Often the nasal cavity is damaged due to trauma and impact. Damage to the internal nasal septum is possible, which adversely affects air permeability. A deviated septum makes breathing difficult. Another common disease is acute rhinitis. So called inflammation of the mucous membranes of the nose. A runny nose can be an independent disease or be one of the symptoms of another infectious lesion. Coryza sometimes goes into chronic form. Chronic rhinitis is often a long-term independent disease. The chronic process is divided into simple, hypertrophic, atrophic and allergic forms. If not treated chronic runny nose, then the patency of the Eustachian tubes may be disturbed and catarrh of the middle ear may develop.

One chronic diseases nasal cavity is called "ozena". The disease manifests itself in a sharp atrophy of the nasal mucosa. Over time, the process affects not only the mucous membrane, but also the bone structures of the shells. The problem has not yet been sufficiently studied, but doctors suggest that its roots lie in external factors and living conditions. Understanding what happens to the air in the nasal cavity, a person is more serious about maintaining health. This allows you to stop pathological processes in a timely manner and avoid serious problems.

During physical activity the amount of air consumed increases, and then the person switches to oral or mixed breathing. Regulation of the frequency and depth of respiratory excursions occurs reflexively, due to irritation of the receptor endings. vagus nerve activating the respiratory center medulla oblongata. If due to different reasons nasal breathing difficult, the breath becomes less deep, which reduces the amount of oxygen entering the body, thereby pathologically affecting the nervous, cardiovascular, circulatory and other systems of the body, especially in children.
During inhalation, due to negative pressure in the chest cavity and in all parts of the respiratory tract, air enters both halves of the nose. Due to the horizontal placement of the nostrils, the air flow rises mainly upward, along the middle and common nasal passages, then changes its direction in an arcuate manner and descends through the choanae into the nasal part of the throat. During exhalation, the air flow through the nasal part of the throat enters the choanae, which are placed vertically, and exits mainly through the lower and middle nasal passages. The nasal cavity accounts for more than half of the total resistance of the respiratory tract, due to its relative narrowness, the tortuosity of the nasal passages and the uneven surface of their walls. The regulation of the air flow to the greatest extent depends on the degree of blood filling of the turbinates.
With a significant swelling of the cavernous bodies, the nasal cavity may become impassable for air.

Protective function of the nose includes reflexes of sneezing and tearing, cleansing, moisturizing and warming the air during its movement through the nasal passages.
Dust particles, mechanical, chemical, thermal and other factors can be irritants of sneezing and tearing reflexes. During a sneeze, air is forcefully pushed out of the nose, while the irritant is also removed. Clearing the nasal cavity is also facilitated by a significant secretion of mucus in response to an irritant.
Air purification is provided through various mechanisms. When the air flow passes through the nose, large dust particles are retained by the hairs of the skin of the vestibule, and smaller ones, together with microorganisms, settle on the mucous membrane covered with a mucous secretion. This is facilitated by narrow and curved nasal passages. Disinfection of microorganisms entering the nasal cavity occurs due to the absorption capacity of histiocyte elements and the bactericidal action of nasal mucus containing mucin and lysozyme. Mucus, along with dust particles and microorganisms, is pushed towards the nasal part of the throat due to the oscillatory movements of the cilia. The fluctuations of the cilia are subject to a certain rhythm (approximately 250 cycles per 1 min), due to which the mucus is pushed in waves from one area to another. This process occurs most intensively in the middle and posterior regions of the respiratory zone. The time of passage of particles from the anterior end of the inferior turbinate to the choanae is 10-12 minutes. Further, the mucus is swallowed along with saliva, and its final neutralization takes place in the stomach. In case of exposure to chemical and physical factors or due to inflammatory processes, the functions of the ciliated epithelium may be impaired.
Humidification of the inhaled air occurs due to the evaporation of mucus secreted by the mucous membrane, tears entering the nasal cavity through the nasolacrimal canal, and interstitial fluid. During the day, the mucous membrane of the nasal cavity of an adult releases approximately 500 ml of moisture.
Warming of the air is carried out due to the heat generated by the surface of the walls of the nose.
The presence of turbinates and mucosal irregularities increases the surface of contact with air. By giving off heat to warm the air passing through the nose, the nasal mucosa cools, so its temperature is normally 2-3 ° C lower than body temperature.

Olfactory function provided by the olfactory zone of the mucous membrane, which contains special sensitive cells - chemoreceptors. The olfactory region originates between the middle part of the middle turbinate and the opposite section of the nasal septum and continues to the roof of the nasal cavity. The aromatic substance, having reached the surface of the olfactory epithelium, dissolves in the mucus layer, in which bundles of olfactory hairs are immersed, binding to receptor sites on the surface of olfactory cells, forming complexes with the protein components of their cytoplasmic membrane, which causes a change in its ion permeability and the emergence of a receptor potential. This causes irritation of specific nervous tissue, which spreads along the paths of the olfactory nerve to the subcortical and cortical centers.
If the olfactory fissure is closed, respiratory hypo- or anosmia occurs. If the receptor apparatus itself is damaged, essential hypo- or anosmia develops. Sometimes the perception of smells is distorted - parosmia or cacosmia occur. For a person, the olfactory function is not vital, but it makes it possible to judge the taste of food, plays a role in gastric secretion, and orients in the environment.

resonator function consists in amplifying various tones of the voice. Small cavities (ethmoid cells, sphenoid sinuses) resonate higher sounds, while large cavities (maxillary and frontal sinuses) resonate lower tones. Since the volume of the cavity in a normal adult is constant throughout life, the timbre of the voice does not change. Small changes in the timbre of the voice occur in case of inflammation of the sinuses due to thickening of the mucous membrane. The position of the soft palate to a certain extent regulates the resonance, delimiting the nasal part of the pharynx, as well as the nasal cavity from the middle sections of the pharynx and larynx, where the sound comes from. At the moment of pronouncing some sounds (m, n), the soft palate hangs freely, the nasal part of the pharynx and choanae remain open. In this case, the voice acquires a nasal tone. Paralysis of the soft palate is accompanied by an open nasal (rhinolalia aperta), obstruction of the nasal part of the pharynx, choanae, nasal cavity is manifested by a closed nasal ( rhinolalia Clausa ).

The nasal cavity is the cavity that is the beginning of the human respiratory tract. It is an air channel that communicates with the external environment in front (through the openings of the nose), and behind - with the nasopharynx. The olfactory organs are located in the nasal cavity, and the main functions are to warm, cleanse from foreign particles and humidify the incoming air.

The walls of the nasal cavity are formed by the bones of the skull: ethmoid, frontal, lacrimal, sphenoid, nasal, palatine and maxillary. The nasal cavity from oral cavity delimited by hard and soft palate.

The external nose is the anterior part of the nasal cavity, and the paired openings at the back connect it to the pharyngeal cavity.

The nasal cavity is divided into two halves, each of which has five walls: inferior, superior, medial, lateral, and posterior. The cavity halves are not quite symmetrical because the septum between them tends to be slightly tilted to the side.

The most complex structure is near the lateral wall. Three nasal conchas hang down on it. These shells serve to separate the upper, middle and lower nasal passages from each other.

In addition to bone tissue, the structure of the nasal cavity includes cartilaginous and membranous parts, which are characterized by mobility.

The vestibule of the nasal cavity is lined from the inside with squamous epithelium, which is a continuation of skin. In the connective tissue layer under the epithelium, the roots of bristle-like hairs and sebaceous glands are laid.

The blood supply to the nasal cavity is provided by the anterior and posterior ethmoidal and sphenoid-palatine arteries, and the outflow is provided by the sphenoid-palatine vein.

The outflow of lymph from the nasal cavity is carried out in the submental and submandibular lymph nodes.

In the structure of the nasal cavity, there are:

• The superior nasal passage, located only in the posterior part of the nasal cavity. As a rule, it is half the length of the average stroke. The posterior cells of the ethmoid bone are open in it;
• The middle nasal passage is located between the middle and lower conchas. Through a canal in the form of a funnel, the middle nasal passage communicates with the anterior cells of the ethmoid bone and the frontal sinus. This anatomical connection explains the transition inflammatory process on the frontal sinus with a runny nose (frontal sinus);
• The inferior nasal passage runs between the floor of the nasal cavity and the inferior concha. It communicates with the orbit through the nasolacrimal duct, which ensures the flow of tear fluid into the nasal cavity. Due to this structure, nasal discharge intensifies when crying and, conversely, the eyes often “watery” with a runny nose.

Features of the structure of the mucous membrane of the nasal cavity

The mucous membrane of the nasal cavity can be divided into two areas:

• The superior turbinates, as well as the upper part of the middle turbinates and nasal septa, are occupied by the olfactory region. This area is lined with pseudostratified epithelium containing neurosensory bipolar cells responsible for odor perception;
• The rest of the mucous membrane of the nasal cavity is occupied by the respiratory region. It is also lined by pseudostratified epithelium, but it contains goblet cells. These cells secrete mucus, which is necessary to humidify the air.

Regardless of the region, the lamina of the mucous membrane of the nasal cavity is relatively thin and contains glands (serous and mucous) and a large number of elastic fibers.

The submucosa of the nasal cavity is quite thin and contains:

• lymphoid tissue;
• Nerve and vascular plexuses;
• glands;
• Mast cells.

The muscular plate of the nasal mucosa is poorly developed.

Functions of the nasal cavity

The main functions of the nasal cavity include:

• Respiratory. The air inhaled through the nasal cavity makes an arcuate path, during which it is cleaned, warmed and moistened. The warming of the inhaled air is facilitated by numerous blood vessels and thin-walled veins located in the nasal cavity. In addition, the air inhaled through the nose exerts pressure on the mucous membrane of the nasal cavity, which leads to the excitation of the respiratory reflex and greater expansion chest than when inhaled through the mouth. Nasal obstruction usually results in physical condition the whole organism;
• Olfactory. The perception of smells occurs due to the olfactory epithelium located in the epithelial tissue of the nasal cavity;
• Protective. Sneezing that occurs as an end irritation trigeminal nerve airborne coarse suspended particles provides protection against such particles. Lachrymation promotes purification by inhalation of harmful air impurities. In this case, the tear flows not only outside, but also into the nasal cavity through the nasolacrimal canal;
• Resonator. The nasal cavity with the oral cavity, pharynx and paranasal sinuses serve as a resonator for the voice.

1. what is the meaning of breathing?

2. how is the nasal cavity arranged?

3. what happens to the air in the nasal cavity?

4. What is the function of the larynx?

5. How does sound arise and form?

6. In which organ does the larynx continue?

7. Tell us about the structure of the trachea?

8. How are the lungs arranged? what are pulmonary flares?

9. What additional functions do the alveoli perform?

• 1. If you do not breathe, then oxygen will not enter the brain, and oxygen starvation. Death is coming
  2. The nasal cavity is divided by a septum into two halves and from behind passes into the upper part of the pharyngeal cavity - the nasopharynx.
  3. In the nasal cavity, the air is cleared of dust and becomes warm.
  4. Functions. 1) Provides air passage. 2) Voice machine. 3) Participates in the act of swallowing
  5. Voice occurs when air from the lungs passes through the vocal cords. The pitch of the voice depends on how fast the connections vibrate. The movement of air, then fills the lungs, then goes out, controls the diaphragm. The muscles of the tongue and lips make the sounds that the connections make understandable. The cavities of the nose, larynx, and chest help to amplify sound through resonance.
  6. After the larynx comes the trachea.
  7. Trachea (from the Greek word trachus, which means "rough") is a tubular unpaired organ, which is a continuation of the larynx and refers to the lower respiratory tract. Its length is approximately 9-11 cm. The transverse diameter does not exceed 15-18 mm, but this indicator depends on age, it is an individual parameter
  8. They are lungs, two bags, which, when inhaled, are filled with atmospheric air. The surface of the lungs is covered from the inside with special vesicles called alveoli. These are the alveoli, and provide the absorption of oxygen from the air, and the release of carbon dioxide.
  Hope it helped.

Attention, only TODAY!

138. Look at the picture. Write the names of the respiratory organ indicated by numbers.

1 - nasal cavity

2 - nasopharynx

3 - trachea

4 - bronchi

5 - bronchial tree

6 - pleura

7 - lung, lung lobes

8 - larynx

139. What happens to the air in the nasal cavity?

The blood warms the air that passes through the nasal cavity. The mucus secreted by the mucous glands humidifies the air and traps dust.

140. Fill in the table.

RESPIRATORY SYSTEM.

Organ name	Functions
nasal cavity	The blood warms the air that passes through the nasal cavity. The mucus secreted by the mucous glands humidifies the air and traps dust.
larynx	it is a voice apparatus that is part of the respiratory tract
epiglottis	closes the entrance to the larynx
trachea	carrying air into the bronchi and lungs. No less important is the protective function of this organ. The mucous membrane of the trachea purifies the passing air, as it can remove particles up to 1-5 microns in size from it. Also, the trachea is an additional resonator for air during sound and speech production.
lungs	serve as excretory organs, CO2 is released from their surface
pleura	there is a fluid that reduces friction

141. Determine which organ is shown in the figure. What are its functions?

The larynx is part of the respiratory tract, performs the following functions: it transfers air through its cavity to the lungs, which ensures the normal operation of the entire respiratory system, and also this organ is directly involved in the respiratory system. The amount of air supplied to the lower Airways, regulated by expansion and contraction of the larynx. Be sure to mention one of its most important tasks - protection. So, while swallowing food, the epiglottis tends to fall, due to which the larynx rises slightly. As a result, it becomes impossible for food to enter the lumen of this organ, which could adversely affect its work. And it is this body that is the voice-forming body.

142. What is the structure of the lungs?

The main organ of the respiratory system is the lungs. They are located in the chest cavity, almost completely hiring it. each lung is covered on the outside with a thin membrane - the pleura. One sheet covers the lung, the other lines the chest cavity, forming a closed receptacle for the lung. Between these sheets is a slit-like cavity that holds some fluid, reducing friction as the lungs move.

143. Explain why the number of lobes in the left and right lungs of a person is not the same.

In the right lung of a person, the number of lobes is greater, and in the left it is less, because. on the left is the heart.