Question

Intrapulmonary pressure in the ________.

a. pressure within the pleural cavity.
b. pressure within the alveoli
c. negative pressure in the intrapleural space
d. difference between atmospheric pressure and respiratory pressure

Answer 1

Intrapulmonary pressure is the pressure within the alveoli and fluctuates with breathing cycles, balancing against atmospheric pressure to enable gas exchange. It is subject to Boyle's law and influenced by transpulmonary pressure.

Step-by-step explanation:

The intrapulmonary pressure is the pressure within the alveoli of the lungs. It fluctuates during the phases of the breathing process, increasing as the alveoli fill with air during inspiration and decreasing during expiration. Intrapulmonary pressure is essential for gas exchange and is precisely regulated to ensure efficient ventilation in response to the body's oxygen demands. It is influenced by the volume of the gas in the lungs, as per Boyle's law, and the transpulmonary pressure, which is the pressure difference between the intrapulmonary pressure and the pressure within the pleural cavity, known as intrapleural pressure.

Atmospheric pressure is another crucial factor in breathing, as the intrapulmonary pressure tends to equalize with atmospheric pressure. Negative pressure, as described in pulmonary physiology, is pressure lower than atmospheric pressure, and it occurs within the pleural cavity, contributing to the lungs remaining inflated under normal conditions.

During pulmonary ventilation, air moves from areas of higher to lower pressure, moving through the airways until intrapulmonary pressure equilibrates with atmospheric pressure. This dynamic process is vital for the inhalation and exhalation of air, which allows the exchange of oxygen and carbon dioxide necessary for the function of the body's cells.

Answer 2

The correct answer is option B- pressure within the alveoli.

Step-by-step explanation:

Intrapulmonary pressure is the pressure within the lungs especially in the alveoli of the lungs so is also known as "intra-alveolar pressure".

This pressure helps in the breathing process as :

1. During inspiration - The thoracic cavity volume increases due to which the intra-pulmonary pressure becomes less than the atmospheric pressure which causes the lungs to inhale about 500 ml of air.

2. During expiration- the thoracic volume decreases which cause the intra-pulmonary pressure larger than atmospheric pressure which causes the lungs to exhale the air.

Thus, option B- pressure within the alveoli is the correct answer.