intrapulmonary

Intrapulmonary is an anatomical term meaning located within the lungs. It is used to describe structures, spaces, or processes that occur inside the pulmonary parenchyma, and it is contrasted with extrapulmonary, which refers to areas outside the lungs.

Intrapulmonary components include the intrapulmonary airways, the portion of the bronchial tree contained within the lung (from segmental bronchi down to the bronchioles); the lung parenchyma, including the alveolar units where gas exchange occurs; and the intrapulmonary vasculature (the pulmonary arteries and veins embedded in lung tissue). The trachea and extrapulmonary bronchi lie outside the intrapulmonary space.

Physiological and clinical usage often concerns intrapulmonary pressure—the pressure inside the lungs, which varies during the respiratory cycle. Intrapulmonary (alveolar) pressure is negative relative to atmospheric pressure during inspiration and becomes positive during expiration. Clinically, intrapulmonary shunt refers to perfusion of nonventilated alveoli, reducing oxygenation. Intrapulmonary edema or hemorrhage denotes fluid or blood within the lung parenchyma. These concepts are often discussed in contrast to intrapleural or extrapulmonary processes.