exchange of O2 and CO2 between the alveoli and circulating blood in the pulmonary capillaries.
lungs containe over 300 million tiny air sacs providing a huge surface area for gas exchange (Diffusion).
an active process in which the intercostal (rib) muscles and the diaphragm contract, expanding the size of the chest cavity and causing air to flow into the lungs
muscular partition that separates the thoracic cavity from the abdominal cavity and aids in respiration by moving up and down
diaphragm relaxes & moves up into original dome shape. This decreases the chest volume & moves air out of the lungs
the process by which molecules spread from areas of high concentratiion, to areas of low concentration
Resistance to Airflow
-pressure is one determinant of airflow
-resistance is the other determinant of airflow
-the greater the resistance the slower the flow
the maximum amount of air that can be exhaled after a maximum inhalation (usually tested with a spirometer)