Dorothy FarrarBronchi
The bronchi are the air-conducting parts of the lungs , which together with the trachea are part of the lower respiratory tract. Collectively, this area of the airways is referred to as the bronchial system.
Definition
With the help of the bronchi, the inhaled air is transported to the alveoli (air sacs in the lungs), where gas exchange takes place. In this way, the lungs are supplied with oxygen-rich air. After the Gauss exchange, the air, which is now enriched with carbon dioxide, is transported or exhaled via the bronchi.
Anatomy
At the level of the second intercostal space, the trachea is divided into a left and right main bronchus (bronchus principalis dexter and sinister). These lead to the left and right lungs. After a short course, each main bronchus divides into lobar bronchi. The left lung consists of two, the right lung of three lobes or lobe bronchi.
The lobar bronchi then further divide into ten segment bronchi each, which branch into very fine branches. The smallest bronchi are only about 1mm in size and are called bronchioles. The last section of the bronchial system is formed by the alveoli (air sacs in the lungs), in which gas exchange takes place.
The branching system can also be compared to a tree: the trachea forms the trunk, which branches out further and further to very small leaves (air sacs). This structure is therefore also referred to as the bronchial tree. The wall structure of the bronchi is also different: The wall structure of the main bronchi is similar to that of the trachea, where elastic wall sections and cartilage alternate.
The further the bronchial tree branches, the more the proportion of cartilage and the number of mucosal glands and goblet cells decrease and the smooth muscle increases. There is a muscular wall in the bronchioles, but no glands or cartilage. The bronchi are surrounded by the smooth muscles in a ring shape and when the muscles contract, the bronchi are also narrowed.
Function
Even the smallest bronchioles lead into the alveolar ducts or alveolar sacs, where the alveoli are arranged in a grape shape. When you inhale, the air travels through the bronchi to the alveoli, with the driving forces being the movements of the diaphragm and chest.
When air enters the alveoli, they inflate and double in diameter. This creates a very large surface. The alveoli are surrounded by a fine network of capillaries, the boundary between the capillaries and the alveoli being called the blood-air barrier.
Gas exchange can take place due to the partial pressure difference between the blood and the alveoli. The carbon dioxide, which then accumulates in the metabolism, is exhaled and the blood is enriched with oxygen. The smaller the alveoli, the faster the heart rate and respiration must be for gas exchange to take place. For this reason, children also breathe faster than adults.
The breathing area is also reduced in the case of pulmonary edema or pneumonia, so that the heart has to work harder. Certain cells in the air sac wall produce a substance called surfactant, a substance that lowers the surface tension of the air sacs in the lungs, preventing the alveoli from collapsing after each breath.
Diseases
A common disease of the bronchi is the so-called bronchitis, in which the mucous membranes of the bronchi are inflamed. Bronchitis can be either acute or chronic. In the case of acute bronchitis, those affected suffer from sputum , cough and sometimes fever . Chronic bronchitis is very common in smokers.
Another chronic disease is bronchial asthma. The airways are narrowed, the mucous membrane swells and the patients suffer from shortness of breath , a dry cough and a feeling of tightness in the chest.
Smokers are also often affected by chronic obstructive pulmonary disease (COPD). The airways are narrowed, which impedes the flow of air. This is followed by coughing, sputum production and shortness of breath .
If fluid builds up in the alveoli, pulmonary edema can occur. This often happens as a result of injury or heart disease. The symptoms are rattling noises when breathing, shortness of breath and sputum production.
Sac-like enlargements in the bronchi are called bronchiectasis. These can be acquired or congenital. Mucus accumulates in the extensions and inflammation can also often occur due to bacteria . Those affected then suffer from a high fever and cough.
When the lung tissue is damaged, the alveoli become overinflated, which is known as pulmonary emphysema. The area for gas exchange is reduced and patients cannot exhale as much stale air. This causes chronic shortness of breath.
One of the most common forms of cancer is bronchial carcinoma, which mainly develops as a result of smoking. Prolonged damage changes the genetic material in the cells, which can lead to the development of a malignant tumor .
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.