Human respiratory system - The mechanics of breathing: Air moves in and out of the lungs in response to differences in pressure. When the air pressure within. Boyle's Law describes the relationship between the pressure (P) and the volume (V) of a gas. The law states that if the volume increases, then the pressure must. In this essay, we provide a brief review of the state of knowledge of the mechanics of breathing at the time the Division of Lung Disease (DLD) of the National.


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Therefore, the contraction and relaxation of certain muscles during breathing causes movement of the lungs, changing the volume of air within the lungs.


Therefore, when the lungs expand increasing the volume of air within them, mechanism of breathing declines. When the pressure of the air outside the lungs is greater than the air inside, air will rush into the lungs, and vice versa. Inspiration Inspiration allows air to be moved into the lungs and requires the contraction of various muscles: The diaphragm and external intercostal muscles contract When the diaphragm contracts, it flattens, pressing down on the abdominal contents and lifting the thoracic cavity.

This leads to an increase in the volume mechanism of breathing the thoracic cavity.

Mechanics of Breathing

The muscle of diaphragm contract which lowers the diaphragm. As a result the size of thoracic cavity increases as well as the lungs expand simultaneously. As the lungs expand, the air pressure inside the mechanism of breathing decreases.

In order to balance the air pressure, air rushes from atmosphere into the lungs through air passage.

The process of inspiration is active, as it needs energy for muscle contraction. If oxygen saturation falls, mechanism of breathing accelerates to increase the volume of Oxygen inspired.

This also occurs when lactic acid is released into the blood following high-intensity exercise.

Mechanics of Breathing

Regulation of breathing Respiration is controlled by the autonomic nervous system, which enables us to alter our breathing without thinking about it. Mechanism of breathing autonomic nervous system consists of two branches, the sympathetic nervous system the pedals and the parasympathetic nervous system the breaks.

At rest, we inspire approximately ml of air per breath and on average we breathe times per minute. The volume of air mechanism of breathing breathe in or out per breath is known as tidal volume, the volume of air we breathe in or out per minute is known as minute ventilation.

Our minute mechanism of breathing is calculated as follows: During inspiration breathing innerve impulses are sent via the phrenic and intercostal nerves which stimulates the inspiratory muscles, the external intercostal and diaphragm, causing them to contract, this stimulation lasts for approximately two seconds, after which, the inspiratory muscles relax and expiration occurs.

The force required to maintain inflation of the lung and to cause airflow is provided by the chest and diaphragm the muscular partition between chest and abdomenwhich are in turn stretched inward by the pull of the lungs.


The lung—chest system thus acts as two opposed coiled springs, the length of each of which is affected by the other. Were it not for the outward traction of the chest on the mechanism of breathing, these would collapse; and were it not for the inward traction of the lungs on the chest and diaphragm, the chest would expand to a larger size and the diaphragm would fall from its dome-shaped position within the chest.

The role of muscles The respiratory muscles displace the equilibrium of elastic forces in the lung and chest in one direction or the other by adding mechanism of breathing contraction.

Human respiratory system - The mechanics of breathing |

During inspiration, muscle contraction is added to the outward elastic force of the chest to increase the traction on the lung required for its additional stretch. When these muscles relax, the additional retraction of lung returns the mechanism of breathing to its equilibrium position.

Contraction of the abdominal muscles displaces the equilibrium in the opposite direction by adding increased mechanism of breathing pressure to the retraction of lungs, thereby further raising the diaphragm and causing forceful expiration. This additional muscular force is removed on relaxation and the original lung volume is restored.