The 7 parts of the lung: functions and characteristics

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.

Then let's see the most important parts of the lung, not without first highlighting its functions.

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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 passage of oxygen present in the external environment and reach the blood and, then, through exhalations, they cause carbon dioxide to pass from the blood to the outside expelled.

The path that the air follows normally begins in the nose, although it can also be introduced through the mouth. Then 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.

Inside the cells metabolic reactions are carried out 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 oxygen necessary for the body to function, they can also be the entry point for many pathogens. That is why the airways are covered with a special mucosa, capable of trapping particles from 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 much 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 cardiac organ is positioned on the left side of the rib cage.

But despite this slight deformity, totally natural and asymptomatic, both lungs, if healthy, perform their role successfully: to be the center of the respiratory system. Because of this, they have special internal structures, which work together to allow gas exchange.

1. 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.

Per se, it is not a part of the lungs, but it is fundamental in the respiratory system, since it is the duct that bifurcates to allow air to enter both respiratory organs and, in turn, giving rise to the right and left main bronchus.

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2. 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. Bronchi

The bronchi are extensions of the trachea, which penetrate the lungs and are responsible for air reaching other lung structures. As the tracheo-bronchial duct descends, it branches out even more, forming small branches called bronchioles.

4. The bronchioles

The bronchioles become narrower and narrower, thus allow gas exchange to occur at its ends, this being the end of the tour.

Although small, the bronchioles are very important, 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. Alveoli

The alveoli are at the end of the bronchioles, and They are made up of small air sacs where gas exchange occurs. The wall of these structures is formed by capillaries which are related to the blood vessels, that is, it is the place where contact with the 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. carbon, which has been generated as metabolic waste after oxygen has been used inside the cells. cells.

In order for red blood cells to bind to 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 uninterruptedly, 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 functions metabolic.

What's more, it is also thanks to these structures that carbon dioxide can be released, before it intoxicates the cells.

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6. Pleura

As we had commented before, the pleura is the structure that covers the lungs, protecting their 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. Diaphragm

Although it is 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 has a shape 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.

Bibliographic references:

• Tomashefski, J.F., Farver, C.F. (2009) "Anatomy and Histology of the Lung". Dail and Hammar’s Pulmonary Pathology.
• Less, N., Soni, N. (2014) "Respiratory Physiology". Clinical Intensive Care Medicine.
• Wahlstedt, R. (2019) "Anatomy of the Lung". Liberty University.
• Latarjet, M, Ruiz-Liard, A and Pró, E.. (2007). Human anatomy. Spain. Pan American.
• Willmore, J. H. and Costill, D. L (2007). Physiology of effort and sport. Texas, United States. Paidotribo.
• Gutiérrez, C. (2004). Physiology and Hygiene. Mexico. Limusa