The respiratory system is represented by various organs, each of which performs a specific function. It contains the airways and the respiratory part. The latter include the lungs, the respiratory tract - the larynx, trachea, bronchi and nasal cavity. The inner part is lined with a cartilaginous framework, which is why the tubes do not collapse. Also on the walls there is a ciliated epithelium, cilia that hold dust and various foreign particles, removing them from the nasal passage along with mucus. Each section of the respiratory system has its own characteristics and performs a specific function.
Nasal cavity
The airways start from the nasal cavity. This organ performs several functions at once: it keeps foreign particles that enter the respiratory system with air, allows you to hear odors, moisturizes, warms the air.
The nasal cavity is divided into two parts by the nasal septum. Behind are the choanae connecting the airways with the nasopharynx. The walls of the nasal passage are formed by bone tissue, cartilage and are lined with mucous membranes. Under influenceirritants, it swells, becomes inflamed.
In the nasal passage, the largest cartilage is the septum. There are also medial, lateral, superior and inferior septa. On the lateral side there are three nasal conchas, between which there are three nasal passages. The upper nasal passage contains a large number of olfactory receptors. The middle and lower sections are considered respiratory.
The initial airways connect to the paranasal sinuses: maxillary, frontal, ethmoid and sphenoid.
Nasal breathing
During breathing, air enters the nose, where it is cleansed, moistened and warmed. Then it goes into the nasopharynx and further into the pharynx, where the opening of the larynx opens. In the pharynx, the digestive and respiratory tracts cross. This feature allows a person to breathe through the mouth. However, in this case, the air passing through the organs of the airways is not purified.
The structure of the larynx
At the level of the sixth and seventh cervical vertebrae, the larynx begins. In some people, it is visually noticeable by a slight elevation. During a conversation, coughing, the larynx shifts, following the hyoid bone. In childhood, the larynx is located at the level of the third cervical spine. In older people, descent occurs to the level of the seventh vertebra.
From below the larynx passes into the trachea. In front of it are the cervical muscles, on the sides - the vessels and nerves.
The larynx has a skeleton represented by cartilaginous tissue. In the lower part is the cricoid cartilage,the anterolateral walls are represented by the thyroid cartilage, and the upper opening is covered by the epiglottis. The back of the organ has paired cartilages. Compared to the front and side, they have a softer structure, due to which they easily change position relative to the muscles. Behind are carob, sphenoid and arytenoid cartilages.
In their structure, the airways are similar to many hollow organs: from the inside they are lined with mucous tissue.
The larynx has three sections: lower, middle and upper. The anatomical complex structure is distinguished by the middle section. On its side walls there is a pair of folds, between which there are ventricles. The lower folds are called vocal folds. In their thickness are the vocal cords, which are formed by elastic fibers and muscles. Between the right and left folds there is a gap, which is called the voice. In men, it is slightly larger than in women.
Structure of the trachea
The trachea is a continuation of the larynx. This airway is also lined with mucous tissue. The length of the trachea is on average ten centimeters. In diameter, it can reach two centimeters.
The walls of the organ have several incomplete cartilaginous rings, which are closed by ligaments. The wall behind the trachea is membranous and contains muscle cells. The mucous membrane is represented by ciliated epithelium and has many glands.
The trachea begins at the level of the sixth cervical vertebra, ends at the level of the fourth or fifth. This is where the trachea divides into two bronchi. Placebifurcation is called a bifurcation.
The thyroid gland lies in front of the trachea. Its isthmus is located at the level of the third ring of the trachea. Behind is the esophagus. Carotid arteries run along both sides of the organ.
In children, the thymus gland blocks the front of the trachea.
The structure of the bronchi
Bronchi begins from the bifurcation of the trachea. They leave almost at a right angle and go to the lungs. On the right side, the bronchus is wider than on the left.
The walls of the main bronchi have incomplete cartilaginous rings. The organs themselves are divided into medium, small and bronchi of the first, second, third and fourth order. In the small caliber there is no fibrocartilaginous tissue, and in the medium caliber there is elastic cartilage tissue, which replaces the hyaline cartilage.
Bronchi of the first order have branching in the lungs into lobar bronchi. They are divided into segmental and further into lobular. Acini extend from the latter.
Structure of the lungs
The airways complete the lungs, which are the largest organs of the respiratory system. They are located in the chest. On both sides of them are the heart and large vessels. There is a serosa around the lungs.
The lungs are cone-shaped with the base pointing towards the diaphragm. The top of the organ is located three centimeters above the clavicle.
There are several surfaces in the human lungs: base (diaphragmatic), costal and medial (mediastinal).
Bronchi, blood and lymph vessels enter the lungs through the mediastinal surface of the organ. They form the root of the lung. Further, the body is divided into two lobes: left and right. There is a cardiac fossa at the anterior edge of the left lung.
The lobes of each lung consist of small segments, among which there is a bronchopulmonary. The segments are in the form of pyramids, the base of which faces the surface of the lung. Each organ has ten segments.
Bronchial tree
The section of the lung, which is somewhat separated from the neighboring ones by a special layer, is called the bronchopulmonary segment. The bronchi of this area are strongly branched. Small elements with a diameter of no more than a millimeter enter the lung lobule, and branching continues inside. These small parts are called bronchioles. They are of two types: respiratory and terminal. The latter are characterized by a transition to the alveolar passages, and they end with the alveoli.
The entire branching complex of the bronchus is called the bronchial tree. The main function of the airways is gas exchange between the air filling the alveoli and the blood.
Pleura
The pleura is the serous membrane of the lung. It covers the body from all sides. The membrane runs along the edge of the lungs to the chest, forming bags. Each lung has its own individual lining.
There are several types of pleura:
- Mural (the walls of the chest cavity are lined with it).
- Diaphragmatic.
- Mediastinal.
- Rib.
- Pulmonary.
Between the pulmonary and parietal pleurais the pleural cavity. It contains a fluid that helps reduce friction between the lungs and pleura during breathing.
The lungs and pleura have different borders. At the pleura, the upper border runs three centimeters above the first rib, and the posterior border is located at the level of the twelfth rib. The anterior border is variable and corresponds to the line of transition of the costal pleura to the mediastinum.
The air-carrying organs perform the respiratory function. It is impossible to live without the organs of the respiratory system.
