Air flow and particle deposition. Patterns in the diseased human lung

Low lung volumes lead to increased airway resistance because there is less traction on the airways. At very low lung volumes, bronchioles may collapse. The viscosity or density of inspired gases can affect airway resistance. The density of gas increases with deep sea diving, leading to increased resistance and work of breathing. Low-density gases like helium can lower airway resistance During a forced expiration, the airways are compressed by increased intrathoracic pressure. Regardless of how forceful the expiratory effort is, the flow rate plateaus and cannot be exceeded. Therefore, the air flow is effort-independent; the collapse of the airways is called dynamic compression. Whereas this phenomenon is seen only upon forced expiration in normal subjects, this limited flow can be seen during normal expiration in patients with lung diseases where there is increased resistance (e. g., asthma) or increased compliance (e. g., emphysema). New words intrapleural внутриплевральный intra-alveolar внутриальвеолярный collapse коллапс viscosity вязкость density плотность 32.PMechanics of breathing Muscles of respiration: inspiration is always an active process ...»