Pulmonary System: Respiration Process and Mechanics of Ventilation

Process of respiration involves pulmonary ventilation, external respiration, internal respiration, and regulation of ______ .

The muscles that cause lung expansion during inspiration are contraction of diaphragm & ______ intercostal.

Mechanics of ventilation involve the e&c of ribs to balance the pressure difference across the chest wall – also protects the lungs and ______ .

Muscles can be expanded and contracted by piston movement of diaphragm to pull the lungs downward and increase volume of ______ cavity.

Pleural Pressure is the pressure of the pleural cavity/fluid in the thin space between the‬ ‭visceral and parietal pleura. Negative pressure is lower than atmospheric (760 mmHg/0 cm H2O). It is -5 cm H2O / 756 mmHg; normal pressure at the beginning of respiration, amount‬ ‭of suction required to hold the lungs open at rest.

The pressure that causes movement of air in and out of lungs is ______ .

Alveolar Pressure is the air pressure inside the alveoli. At rest, it is 760 mmHg/0 reference pressure (no air flow). During inspiration (758 mmHg/–1 cm H2O); lower than atmospheric pressure. During expiration (762 mmHg/+1 cm H2O); higher than atmospheric pressure.

Transpulmonary Pressure is the difference between alveolar & pleural pressures. It is a measure of forces of lungs that tend to collapse the lungs. Also known as "recoil pressure".

Compliance of the Lungs refers to how much effort is required to stretch the lungs and chest wall. Increase compliance equals easier expansion. Decrease compliance equals resistance expansion. It depends on the ______.

Airway Resistance is regulated by the ANS (autonomic nervous system) and by the degree in contraction or relaxation of smooth muscle. During inspiration, lung expansion leads to bronchi enlargement, ↑ increase of airway diameter, and ↓ decrease of air resistance. During expiration, lung collapse leads to bronchi reduction, ↓ decrease of airway diameter, and ↑ increase of air resistance.