Therefore it is necessary to have highly efficient mechanisms for exchange of O 2 . 2 . Lumenal obstruction 1 . Exudate or compromised wall integrity result in obstruction. Cystic fibrosis -defective gene for a chloride channel resulting in secretion of a copious, thick mucous secretion. Primarily affects lung and pancreas.
Secretions obstruct airways and impede action of cilia.
Conditions from within the wall of the lumen 1 . Destruction of lung parenchyma results in decreased distending force on airways. Low compliance but airway collapse during expiration. Hypoxia and adaptation to high P CO2 3. Can be intra or extra pulmonary in origin.