Respiratory Physiology

Major Function Supply the body with oxygen and dispose of carbon dioxide (CO2) To do this, at least 4 distinct events must occur Collectively called respiration

1. Pulmonary Ventilation Air must move in and out of the lungs so the alveoli are continuously changed and refreshed Commonly called “breathing”

2. External Respiration Gas exchange (oxygen loading and CO2 unloading) between the pulmonary blood and alveoli EXternal respiration = gas exchange between the blood and body EXterior

3. Respiratory Gas Transport Gases must be transported to and from the lungs and tissue cells of the body via the bloodstream

4. Internal Respiration Gas exchanges must be made between the lungs and tissue cells INternal respiration = gas exchanges between blood and cells INside the body

Mechanics of Breathing Breathing (aka pulmonary ventilation) depends on volume changes in the thoracic cavity Volume changes lead to pressure changes, which lead to the flow of gases to equalize the pressure

Chemistry Invasion Pressure: created by the gas molecules hitting each other and the walls of the container It is inversely related to volume That is, when there is high pressure, there is low volume Gases always conform to the shape of the container and, unlike the container, fill its container Therefore, in a large volume, the gas molecules will be farther apart and the pressure will be low On the flip side, if the volume is reduced, the gas molecules will be closer together and the pressure will rise

Inspiration Inspiratory muscles Diaphragm External intercostals The muscles in between your ribs; you eat this when you order baby back ribs