Mechanism of Breathing Explained

Hey everyone, It is a good time to be here today. Thanks a lot for everyone who finds time to read through my post, and for everyone who leave a comment, it means a lot to me. In today's post, I will be looking into breathing and the mechanism of breathing. We all know that breathing is important for our living, as we exchange oxygen and carbon(iv)oxide which we breathe. Study shows that humans cannot stay above 4 minutes or so, without oxygen before Permanent brain damage begins. How does the process of breathing goes in the body, what is the mechanism of breathing. Take a deep breath and let us enjoy the breathtaking (I mean breath giving) post.

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To start with breathing, we need to understand the organs responsible for the exchange of the gases, and in humans, we know that the lungs are responsible in the process. It is important to know that the lungs are found in the thoracic cavity/region of the body. The lungs are divided into two part, the right lung, and the left lung, which are separated by the mediastinum. The right lung is larger than the left lung, and has three lobes (the superior lobe, the middle lobe, and the inferior lobe), while the left lung has two lobes (the superior lobe, and the Inferior lobe). The Lung is surrounded by a serous membrane known as the Visceral pleura, and around the lungs is the parietal pleura, which makes up the Pleural cavity.

For breathing to take place, the thoracic region has to be increased vertically by pushing organs downwards, and horizontally, by increasing the ribs' width. Between ribs are the intercostal muscles, which are required for respiration. The intercostal muscles are External, Internal, and Innermost intercostal muscles. The intercostal muscle and the Diaphragm are important muscle for respiration. The lungs have an intrapulmonary pressure of 760MmHg, an Intrapleural pressure of 756mmHg, and the Atmosphere has an atmospheric pressure of 760mmHg. In the lungs, breathing causes a change in the intrapulmonary volume, which affects the intrapulmonary pressure of the lungs.

During Inspiration (breathing in), the muscles involved are the diaphragm and the intercostal muscles. The diaphragm divides the thoracic region from the abdominal cavity, and when the intercostal muscles, the sternocleidomastoid muscle, and the diaphragm constrict, the diaphragm pulls downward, creating a vertical space, allowing the vertical increase in volume of the lungs. The external intercostal muscles are responsible for elevating the costals during inhalation. The sternocleidomastoid muscle found around the neck elevates the sternum during inhalation, thereby causing the scalene which are attached to the first rib to elevate the ribs. Another muscle responsible for inhalation is the Pectoralis minor (Pec Minor). The Pec Minor is attached to the 3rd, 4th, and 5th ribs. The Rib Cage is elevates by the Pec Minor during inhalation. During inhalation, the diaphragm contracts, moving downwards, allowing the intrapulmonary volume increases, and causing the intrapulmonary pressure of the lungs to reduce (a difference of 1mmHg), thereby causing oxygen to go into the lungs, in the form of diffusion. During normal quiet breathing, not all these muscles are stressed, only the diaphragm and the external intercostal muscles are required, but during stressful breathing, or deep inspirations, muscles such as the Pec minor, sternocleidomastoid muscle, and scalene, are required.

During Exhalation, especially in quiet expiration, the intercostal muscle and the Diaphragm relaxes, letting air out, also the lungs recoils back to its normal size after expanding, causing air to leave the lungs and be exhaled. In deep expiration, the internal intercostal muscle reduces/pull down the rib, thereby reducing the volume of the lungs during breathing out. Also, the Rectus Abdominis muscle of the abdomen also pulls down the ribs during expiration. Other muscles that help during expiration are the External Oblique, the Internal Oblique, and the Tranversus abdominus. They pull down the ribs during deep exhalation breathing. This said, it is important to know that during exhalation, the diaphragm goes back to its normal position, and the intrapulmonary volume decreases causing the intrepulmonary pressure to increase to 761mmHg, which is 1mmHg above atmospheric pressure. Humans exhale carbon(iv)oxide, inhale oxygen, and the cycle continues.

Breathing isn't actually something we often control all the time, although, we can have control over it for a very little time, in cases where we hold our breath and control when we want to breathe in and out, but it isn't for a long time, as our brain overrides our control of it. Breathing is controlled by the medulla oblongata, in the brain stem. In the medulla oblongata, is the dorsal respiratory group neurons which sends signals to the spinal cord sends the information to the phrenic nerve which controls the diaphragm. In the medulla is another respiratory group known as the ventral respiratory group neuron, which sends signals to the respiratory muscles during forced or deep breathing both for inhaling and exhaling. The Cerebral cortex helps during the little time of conscious control of breathing. It sends signals to the medulla oblongata, to regulate the breathing.

Conclusion

It is important that we understand that breathing is the process of moving air into the lungs and out of the lungs, to help oxygenate the blood as well as take out carbon(iv)oxide from the blood. When the lungs expand, it allows for air to get into it, and when it relaxes, air leaves the lungs. It is important to know that both the nasal cavity and the oral cavity go to the pharynx (nasopharynx for the nose and the oropharynx). From the pharynx it goes to the laryngeal prominence, after which it goes to the trachea,then to the bronchi where it goes to the lungs. In the lung, the bronchi sends the bronchioles, then to the alveoli where gaseous exchanges take place.

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