Question

Explain the process of pulmonary ventilation. How do normal inspiration and expiration occur? Use the term volume and pressure changes that occur and how they occur in your discussion.

Answer 1

Pulmonary ventilation is commonly referred to as breathing.Pulmonary ventilation comprises two major steps: inspiration and expiration. Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs . A respiratory cycle is one sequence of inspiration and expiration.

During inspiration, the diaphragm contracts and pulls downward while the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

During expiration, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs contract and air is forced out.

Pulmonary ventilation is dependent on three types of pressure: atmospheric, intra-alveolar, and interpleural. Inspiration and expiration are dependent on the differences in pressure between the atmosphere and the lungs.

At a constant temperature, changing the volume occupied by the gas changes the pressure, as does changing the number of gas molecules. Boyle’s law describes the relationship between volume and pressure in a gas at a constant temperature. Boyle discovered that the pressure of a gas is inversely proportional to its volume.

Pressure and volume are inversely related (P = k/V).

P1V1 = P2V2

P1 is the initial pressure and V1 is the initial volume, whereas the final pressure and volume are represented by P2 and V2, respectively.