Question

What is Boyle’s law and how does this relate to respiration (What happens to the volume of the chest cavity when we need to inhale? How does this the pressure compared to atmospheric?

Similarly, what causes expiration?

Answer 1

Hi Answer:

Boyle’s law is the basic chemistry law. It was discovered by Robert Boyle in 1662. This law explains the behavior of gas which is held at a constant temperature. According to this law at the fixed temperature, the volume of gas is inversely proportional to the pressure exerted by the gas.

P inversely proportional to V (where P is pressure and V is the volume of gas)

How Boyles Law is related to respiration

Respiration is the process by which composes two activities i.e. inspiration and expiration. The mechanism of respiration is discussed in subsequent sections. Our body is divided into two major cavities i.e. thoracic and abdominal cavity. The thoracic cavity hold lungs which are protected by the ribcage and at the base of ribcage there is a large smooth muscle which is known as the diaphragm. This diaphragm separates the thoracic cavity from the abdominal cavity. The inhalation (inspiration) or exhalation (expiration) are the two processes which depend on the relaxation and contraction of the diaphragm.

When the diaphragm is contacted it pull down towards the abdominal cavity which increases the volume and lower the pressure of lungs and creates empty space which forms the vacuum. This reduction in pressure in thoracic cavity pull the air from outside towards the lungs. The route of air entry to the body is nasal passage to pharynx, Larynx, trachea, bronchi, bronchioles, and lungs. This process is known as the inhalation or inspiration.

During the relaxation of the diaphragm, the muscle is compressed due to that the volume of the thoracic cavity is reduced which increases the pressure and this pressure pumps the air molecules from lungs to the bronchioles, into the bronchi, trachea, larynx, and pharynx and exit the body through the nasal passages. This whole process in which air pumped out from the body is known as exhalation or expiration.

These both movements of air i.e. inspiration (inhalation) and expiration (exhalation) is due to the change in the pressure and volume of the thoracic cavity and this relationship is exactly similar to the finding of the Boyles Law.

How does the pressure of thoracic cavity is compared to atmospheric the pressure?

The respiration follows the rule that air moves from higher pressure are to lower pressure area. Whenever the thoracic cavity pressure becomes equal to atmospheric pressure the respiration process will stop. In case of inhalation, the pressure inside the thoracic cavity is reduced so air from higher pressure (atmosphere) runs towards the thoracic cavity. And in case of exhalation (expiration), the thoracic cavity pressure becomes higher than atmospheric pressure due to this change in pressure air rushes from lungs to the atmosphere. This all pressure management is done by the contraction and relaxation of the diaphragm.