Question

question 66
which of the following pressures is always positive?
atmospheric pressure
intrapleural pressure
transpulmonary pressure
intra - alveolar pressure

Explanation:

Atmospheric pressure is the pressure exerted by the weight of the atmosphere. It is always positive as it is the force per unit area exerted by the air above. Intrapleural pressure can be negative (less than atmospheric pressure) during normal breathing. Transpulmonary pressure is the difference between intra - alveolar and intrapleural pressures and can vary. Intra - alveolar pressure also changes during the respiratory cycle (e.g., it is lower than atmospheric during inhalation and higher during exhalation in normal breathing).

Answer:

Atmospheric pressure