The bronchial tree in the structure is a trachea and bronchial trunks extending from it. The combination of these branches constitutes the structure of the tree. The structure is identical in all people and does not have striking differences. The bronchi are tubular branches of the main trachea that have the ability to conduct air and connect it to the respiratory parenchyma of the lung.
Structure of the main bronchi
The first branches of the trachea are the two main bronchi, which depart from it at almost a right angle, and each of them is directed towards the left or right lung, respectively. The bronchial system is asymmetric and has slight differences in the structure of different sides. For example, the main left bronchus is slightly narrower in diameter than the right, and has a greater length.
The structure of the walls of the main air-conducting trunks is the same as that of the main trachea, and they consist of a number of cartilaginous rings, which are interconnected by a system of ligaments. The only distinguishing feature is that in the bronchi, all rings are always closed and do not have mobility. In quantitative terms, the difference between versatile trunks is determined by the fact that the right one has a length of 6–8 rings, andleft - up to 12. Inside, all the bronchi are covered with a mucous membrane.
Bronchial tree
The main bronchi begin to branch at their end. Branching occurs into 16–18 smaller tubular leads. Such a system, due to its appearance, was called the “bronchial tree”. The anatomy and structure of the new branches differ little from the previous sections. They have smaller dimensions and a smaller diameter of the airways. Such a branching is called share. It is followed by segmental ones, while branching into the lower, middle and upper lobar bronchi is formed. And then they are divided into systems of apical, posterior, anterior segmental pathways.
Thus, the bronchial tree branches more and more, reaching the 15th order of division. The smallest bronchi are lobular. Their diameter is only 1 mm. These bronchi also divide into terminal bronchioles ending in respiratory ones. At their ends are the alveoli and alveolar ducts. The respiratory bronchiole system is a collection of alveolar ducts and alveoli that fit tightly together and form the lung parenchyma.
In general, the wall of the bronchi consists of three shells. These are: mucous, muscular-cartilaginous, adventitial. In turn, the mucosa is densely lined and has a multilayer structure, is covered with cilia, secretes secretions, has its own neuroendocrine cells capable of forming and releasing biogenic amines, as well as cells involved in the processesmucosal regeneration.
Physiological functions
The main and most important function of the bronchus is to conduct air masses into the respiratory parenchyma of the lung and vice versa. The bronchial tree is also a security system for the respiratory system and protects them from dust, various microorganisms, and harmful gases. The regulation of the volume and speed of the air flow passing through the bronchial system is carried out by changing the difference between the pressure of the air itself in the alveoli and in the surrounding air. This effect is achieved through the work of the respiratory muscles.
On inhalation, the diameter of the lumen of the bronchi changes towards expansion, which is achieved by regulating the tone of smooth muscles, and on exhalation it decreases significantly. The resulting disturbances in the regulation of smooth muscle tone are both causes and consequences of many diseases associated with the respiratory organs, such as asthma, bronchitis.
Dust particles entering with air, as well as microorganisms, are removed by moving mucous secretions through the cilia system in the direction of the trachea to the upper respiratory organs. The excretion of mucus containing impurities is carried out by coughing.
Hierarchy
The branching of the bronchial system does not occur randomly, but follows a strictly established order. Bronchial hierarchy:
- Main.
- Zonal - second order.
- Segmental and subsegmental are 3rd, 4th, 5th orders.
- Small - 6-15 orders of magnitude.
- Terminal.
This hierarchy is fully consistent with the division of lung tissue. So, the lobar bronchi correspond to the lobes of the lung, and the segmental bronchi correspond to the segments, etc.
Blood supply
The blood supply to the bronchi is carried out with the help of the arterial bronchial lobes of the thoracic aorta, as well as with the help of the esophageal arteries. Venous blood is drained through the unpaired and semi-unpaired veins.
Where are the human bronchi located?
The chest contains numerous organs, vessels. Formed by the rib-muscular structure. It is designed to protect the most vital systems located inside it. Answering the question: “Where are the bronchi located?”, It is necessary to consider the location of the lungs, the blood, lymphatic vessels and nerve endings connecting to them.
The dimensions of the human lungs are such that they occupy the entire front surface of the chest. The trachea and bronchi, located in the center of this system, are located under the anterior spine, located in the central part between the ribs. All bronchial leads are located under the costal mesh of the anterior sternum. The bronchial tree (the scheme of its location) associatively corresponds to the structure of the chest. Thus, the length of the trachea corresponds to the location of the central spinal column of the chest. And its branches are located under the ribs, which can also be visually identified as a branching of the central column.
Bronchi examination
Respiratory system research methods include:
- Interrogation of the patient.
- Auscultation.
- X-ray examination.
- MRI of the lungs and bronchi.
Research methods, their purpose
When interviewing a patient, possible factors that can affect the state of the respiratory system, such as smoking, harmful working conditions, are established. On examination, the doctor pays attention to the color of the patient's skin, the shape of the chest, the frequency of breaths, their intensity, the presence of cough, shortness of breath, sounds unusual for normal breathing. They also carry out palpation of the chest, which can clarify its shape, volume, the presence of subcutaneous emphysema, the nature of voice trembling and the frequency of sounds. A deviation from the norm of any of these indicators indicates the presence of any disease that is reflected in such changes.
Auscultation of the lungs is performed using an endoscope and is performed to detect changes in breath sounds, the presence of wheezing, whistling and other sounds uncharacteristic of normal breathing. Using this method, by ear, the doctor can determine the nature of the disease, the presence of swelling of the mucous membranes, sputum.
X-ray plays one of the most important roles in the study of diseases of the bronchial tree. A survey radiograph of the human chest allows you to distinguish the nature of the pathological processes occurring in the respiratory system. The structure of the bronchial tree is clearly visible and can be analyzed to identify pathological changes. The picture showschanges occurring in the structure of the lungs, their expansions, bronchial lumen, thickening of the walls, the presence of tumor formations.
MRI of the lungs and bronchi is performed in the anteroposterior and transverse projections. This makes it possible to examine and study the state of the trachea and bronchi in their layered image, as well as in cross section.
Treatment methods
Modern methods of treatment include both surgical and non-surgical treatment of diseases. This is:
- Therapeutic bronchoscopy. It is aimed at removing bronchial contents and is performed in the treatment room, under the influence of local or general anesthesia. First of all, the trachea and bronchi are considered to establish the nature and area of damage from the effects of inflammatory changes. Then washing is carried out with indifferent or antiseptic solutions, medicinal substances are introduced.
- Rehabilitation of the bronchial tree. This method is the most effective known and includes a number of procedures aimed at cleansing the bronchial tract from excess mucus, eliminating inflammatory processes. For this, the following can be used: chest massage, the use of expectorants, the installation of special drainage up to several times a day, inhalations.
Providing the body with oxygen, which means ensuring the body's ability to live, is carried out due to the coordinated work of the respiratory system and blood supply. The relationship of these systems, as well as the speed of the processes, determinethe ability of the body to control and carry out various processes occurring in it. When the physiological processes of respiration are changed or disturbed, the state of the whole organism as a whole is negatively affected.
