Respiratory system

The respiratory system (systema respiratorium), or respiratory apparatus (apparatus respiratorius), supplies the body with oxygen and removes carbon dioxide from it. This system consists of the respiratory tract and paired respiratory organs - the lungs. In accordance with the location of the respiratory tract are divided into upper and lower divisions. The upper respiratory tract includes the nasal cavity, nasal and oral parts of the pharynx. The lower respiratory tract includes the larynx, trachea, bronchi (bronchial tree). Respiratory tracts are tubes of different size and shape, the lumen of which is preserved due to the presence in their walls of the bone or cartilaginous skeleton. From the inside, from the side of the lumen, the walls of the respiratory tract are lined with a mucous membrane, which is covered with a ciliated epithelium. In the mucosa, there are many glands secreting mucus, and blood vessels. Due to this, the airways perform not only air-conducting, but also protective function. In them, the air is cleared of foreign particles, moistened, warmed.

In the lungs, gas exchange takes place. From the alveoli of the lungs through diffusion into the blood of the pulmonary capillaries oxygen enters, and back - from the blood into the alveoli leaves carbon dioxide.

The respiratory system includes a complex organ, the larynx, which performs not only an air-conducting, but also a voice-forming function.

Respiratory organs

The trachea begins at the lower border of the larynx at the level of the VI-VII cervical vertebrae and ends at the level of the IV-V thoracic vertebrae, dividing into the right and left main bronchi.

Mediastinum

The mediastinum is a part of the thoracic cavity bounded by the sternum in front, the spine in the back, and the right and left mediastinal pleura on the sides.

Pleura

The pleura is a thin serous membrane that envelops each lung (visceral pleura) and lines the walls of its pleural cavity (parietal pleura).

Development of the respiratory system

The development of the external nose and nasal cavity is associated with the formation of the visceral skeleton of the head, oral cavity and olfactory organs. The development of the larynx, trachea and bronchi occurs in connection with the transformation of the primary intestine of the embryo. On the ventral wall of the primary intestine, in the area of the border of the pharyngeal and trunk intestines, a saccular protrusion is formed.

Variants and anomalies of the respiratory organs, pleura and mediastinum

External nose. The number of nasal cartilages varies, often their number is less than usual. In 20% of cases, the right and left vomeronasal cartilages are present in the back of the nasal septum. The size and shape of the nose, the configuration of the nostrils are very variable.

Nasal cavity

The nasal cavity (cavum nasi) is divided by the nasal septum into right and left halves. In front of the face, the nasal cavity opens through the nostrils, and at the back, through the choanae, it communicates with the nasopharynx.

Nose: symptoms of diseases in adults and children

The external nose (nasus externus) consists of the root, back, apex and wings of the nose. The root of the nose (radix nasi) is located in the upper part of the face, separated from the forehead by a notch - the bridge of the nose. The lateral sections of the external nose are connected along the midline by the back of the nose (dorsum nasi), ending in front with the apex.

Larynx

The larynx performs respiratory and voice-forming functions, and protects the lower respiratory tract from foreign particles. The larynx resembles an irregularly shaped tube, widened at the top and narrowed at the bottom.

Lungs

The right and left lungs are located in the chest cavity, each in its own half, in the pleural sacs. Between the lungs are the organs of the mediastinum: the heart with the pericardium, the aorta and the superior vena cava, the trachea with the main bronchi, the esophagus, the thymus, the lymph nodes, etc.

Respiratory bronchus

As the caliber of the bronchi decreases, their walls become thinner, the height and number of rows of epithelial cells decrease. Non-cartilaginous (or membranous) bronchioles have a diameter of 1-3 mm, goblet cells are absent in the epithelium, their role is performed by Clara cells, and the submucosal layer passes into the adventitia without a clear boundary.

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