LUNG RESPIRATION: CHARACTERISTICS, PROCESS, PHASES - ANATOMY AND PHYSIOLOGY - 2024

The breathing lung is the gas exchange process occurring within the lungs, where it supplies the necessary oxygen directly organism in the blood and releases carbon dioxide. Respiration in humans occurs approximately twelve to twenty times per minute thanks to the action of the respiratory system.

Despite having a certain conscious control over breathing, the vast majority of the time it is an involuntary and instinctive act. The respiratory center (CR) located in the brainstem is in charge of this process.

Depending on the needs of the body and levels of oxygen versus carbon dioxide, the CR receives chemical, hormonal and nervous system signals, with which it controls the frequency and speed at which the respiratory system acts.

Anatomy of lung respiration

The two lungs are the primary organs of the respiratory system that expand or contract thanks to the action of the diaphragm located below them. The lungs are covered by the rib cage and ribs, which have a certain radius of expansion to allow the lungs to fill with air.

The mouth and nose are responsible for filtering the air that enters the body. It is then transported through the throat into the windpipe.

The trachea divides into two air channels called bronchi, and these in turn branch out within each lung into smaller tubes called bronchioles.

The bronchioles end in the tiny sacs called alveoli, which is where gas exchange finally takes place, specifically where the alveoli connect with the blood capillaries.

From this point on, the distribution of oxygen throughout the body is the task of the circulatory system. The heart pumps the blood carrying oxygen to all cells; to the most distant and / or hidden corners of the body.

Once this is achieved, carbon dioxide is transported in the blood by the circulatory system back to the lungs, where the blood capillaries dispose of it in the alveoli and these expel it through the bronchi, towards the throat and is released lately in the ambient.

Stages or phases of the breathing process

The act of breathing is described as the movement of air in and out of the lungs. The process begins with inhalation or inspiration: the diaphragm muscle, when contracting downwards, creates a vacuum that expands the thoracic cavity and, consequently, the lungs expand causing air to be sucked in from the nose or mouth.

Air passes through the trachea and is distributed through the intricate channels of the brachial tree and enters the tiny alveolar sacs where oxygen crosses the walls of the blood capillaries. Here the hemoglobin protein in the red blood cells helps carry oxygen from the sacs to the blood.

At the same time, carbon dioxide is released from the capillaries, emptied into the lung, and directed out of the body on exhalation or expiration. The diaphragm relaxes by moving upward, causing the space in the thoracic cavity to shrink back to its original position.

Air filled with carbon dioxide is expelled from the lung into the windpipe and then exits through the mouth or nose into the environment. Exhaling is considered a passive movement, since the body makes no effort to expel the air.

Relationship with pressure in air

According to Boyle's law, in closed spaces pressure and volume are inversely related; with the volume reduction the air pressure increases and if the volume is increased the pressure decreases.

Another law tells us that when two media with different air pressure, when a communication channel opens, the air by nature will seek to distribute itself to equalize the pressure in both media. This phenomenon gives the impression that the air is being sucked from the medium with higher pressure to the medium with lower pressure.

A well-known example that illustrates this law is the cockpits of airplanes; specifically if any hatch is open while in the heights. If this happens, the internal air of the aircraft will be completely sucked out of the cabin until it equals the atmospheric pressure outside. On the planet, the higher the altitude, the lower air pressure.

In respiration, the exchange of air between the lungs and the atmospheric environment also depends on the pressure between the two media. To understand the mechanics of respiration in detail, it is necessary to keep in mind the inverse relationship between volume and pressure.

During the inhalation process, when the volume of the lungs increases the pressure inside decreases. In relation to the environment outside, the pressure at that precise moment is less than atmospheric.

This difference causes the air to quickly go from a medium of higher pressure to a lower pressure - thus balancing both mediums -, resulting in the filling of the lungs.

During exhalation the process is reversed. Pressure within the lungs increases when the diaphragm relaxes the chest cavity seeks to reduce its size. To release the pressure, the air is expelled into the environment, thus balancing with atmospheric pressure.

Fun facts related to breathing

As was said previously, respiration is responsible for supplying oxygen to the blood, and this in turn is responsible for oxygenate the entire body. No cell in the body can live without being oxygenated regularly, this makes respiration one of the most important functions of the human being.

The respiratory system has elements inside it that help prevent dangerous substances from entering the lungs.

From hairs in the nose that serve to filter large particles, to microscopic hairs - called cilia - along the respiratory tract that keep the air passages clean. Cigarette smoke does not allow these filaments to function properly, causing health problems and respiratory diseases such as bronchitis.

The mucus produced by the cells of the trachea and bronchial tubes keeps the respiratory tract lubricated and helps stop dust, bacteria and viruses, allergic substances, among others.

In this particular there are also functions subordinate to respiration that serve to self-maintain the released air passages; like coughing and sneezing.

References

1. OpenStax College. Anatomy and Physiology - The Respiratory System. OpenStax CNX. philschatz.com.
2. What is Respiration. Heath Hype.com. Copyright 2017 Healthhype.com
3. Inc. ADAM Medical Encyclopedia. MedlinePlus. Copyright 1997-2017 ADAM medlineplus.gov.
4. How the Lungs and Respiratory System Work. (2014) WebMD Medical Reference. WebMD, LLC. webmd.com.
5. The Mechanics of Human Breathing. Boundles.com.
6. Explore How The Lungs Work. (2012) National Heart, Lung and Blood Institute - National Institutes of Health. US Department of Health & Human Services. nhlbi.nih.gov.
7. Effective Breathing. Smart Breathe. Copyright 2014. smart-breathe.com