Summary about the different parts of the human lungs, with explanations of what they do.
Throughout the day, we breathe about 21,000 times, circulating about 8,000 liters per day through our lungs.
They are continuously working and, in fact, they cannot stop, since the rest of the organs of the body depend on their functioning. Not only because they oxygenate the blood, but it is also thanks to the action of the lungs that we can eliminate carbon dioxide, a residue which is toxic to cells.
Next we are going to see the most important parts of the lung, but not without first highlighting their functions.
The parts of the lung and their functions
The lungs are very important organs for the body, since it is thanks to them that gas exchange can be carried out. First, by inhaling, they allow the oxygen present in the external environment to pass through and reach the blood, and then, by exhaling, they cause the carbon dioxide to pass from the blood to the outside, being expelled.
The path that the air follows normally begins in the nose, although it can also be introduced through the mouth. Afterwards, the air passes through the pharynx, then the larynx and then the trachea, from where it will descend until it bifurcates and enters each of the two lungs that the human body has.
Metabolic reactions take place inside cells that require energy, which is extracted by breaking down the oxygen molecules. In turn, these oxygen molecules bind to carbon molecules, producing carbon dioxide, which is a toxic waste for the cell. That is why breathing is doubly important, since it allows these metabolic reactions to take place and prevents them from being intoxicated.
But in the same way that they are the way to obtain the oxygen necessary for the body to function, they can also be the entry point for many pathogens. This is why the respiratory tract is covered with a special mucosa, capable of trapping particles from the outside, such as dust and germs, which, if not properly stopped, would seriously harm the health of the individual in general and the lung in particular.
Main parts of the lung
The lungs are two organs that resemble two pinkish balloons, which occupy a large part of the rib cage, along with the heart. In fact, it is because of the location of the heart that the lungs are not perfectly symmetrical with each other. The left lung is slightly smaller, since, at least in most people, the heart organ is positioned on the left side of the rib cage.
But despite this slight deformity, totally natural and asymptomatic, both lungs, if healthy, satisfactorily play their role: being the center of the respiratory system. Because of this, they have special internal structures, which work together to allow gas exchange.
1. The trachea
The trachea is the respiratory passage that begins in the larynx, descending vertically to the fourth thoracic vertebra, more or less at the level of the heart.
In itself, it is not a part of the lungs, but it is essential in the respiratory system, since it is the duct that bifurcates to allow the entry of air into both respiratory organs and, in turn, giving rise to the right main bronchus and left.
2. The lobes
The lungs are divided into well-defined sections, called lobes. These lobes are folds in the membrane that lines the lungs, called the pleura.
These lobes fulfill a fundamental function, since they are the ones that allow breathing to occur correctly. It is thanks to them that the lungs can expand when breathing in air.
But, as we were commenting before, because of the heart the lungs are not symmetrical, and this also affects the number of lobes. While the right lung, larger, is divided into three lobes, upper, middle and lower, the left, smaller, only has two, being the lower and the upper.
3. The bronchi
The bronchi are extensions of the trachea, which penetrate into the lungs and are responsible for the air to reach other lung structures. As the tracheo-bronchial duct descends, it branches out even more, forming small branches called bronchioles.
4. The bronchioles
The bronchioles are becoming narrower and narrower, in order to allow the exchange of gases that will occur at their ends, this being the end of the journey.
Although small, bronchioles are of great importance, and that is why there are about 300 thousand in each lung. It is from these structures that the air will reach the following structure: the pulmonary alveoli.
5. The alveoli
The alveoli are at the end of the bronchioles, and are made up of small air sacs where gas exchange occurs. The wall of these structures is formed by capillaries which are related to blood vessels, that is, it is the place where contact with blood is established.
Therefore, it is in the alveoli where breathing takes place, properly speaking, while the rest of the structures of the respiratory system are responsible for making the air reach this point.
Gas exchange begins when the alveoli enrich the blood with oxygen, which passes into the bloodstream by simple diffusion through the capillary walls.
With oxygen in the blood, the red blood cells reach the alveolar capillaries loaded with carbon dioxide, which has been generated as metabolic waste after oxygen has been used inside the cells.
For the red blood cells to be able to bind to the newly arrived oxygen, they must release the carbon dioxide they carry, which will be collected by the alveoli and, later, will be eliminated to the outside by means of expiration.
Gas exchange occurs without interruption, and it is thanks to the alveoli that the oxygen that we introduce from the outside reaches all the cells of the organism, being able to carry out its metabolic functions.
Furthermore, it is also thanks to these structures that carbon dioxide can be released, before it intoxicates the cells.
6. The pleura
As we mentioned before, the pleura is the structure that covers the lungs, protecting its interior and having only two openings, through which the two main bronchi enter.
The pleura is made up of connective tissue, which consists of a cell membrane whose function is to support the internal parts of the lung. This membrane is also covered by a special mucosa that makes the lungs lubricated.
Thanks to the pleura, the lungs have structural support, in addition to allowing them to expand and contract, avoiding friction with the rib cage and absorbing the impact in case of suffering a blow. This keeps the bronchi, bronchioles, and alveoli intact.
7. The diaphragm
Although not part of the lungs, the diaphragm is a very important structure for the proper functioning of the respiratory system. It is a muscle that is located below the lungs and is shaped similar to that of a vault.
This vault has the function of contracting when you breathe in, preventing the lungs from having obstacles when expanding their volume. In turn, the diaphragm relaxes during expiration.
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