At rest, expiration is a(n) ________ process that involves ________.

Pulmonary ventilation is the process of air flowing into and out of the lungs. It's also known as breathing.  Air flows into the lungs during inhalation and out of the lungs during exhalation. This happens because of pressure differences between the atmosphere and the gases inside the lungs.  The volume of pulmonary ventilation is the total amount of air exhaled after maximal inhalation. It's about 4800mL and varies according to age and body size.  The ease of air passage and the amount of energy required for ventilation are influenced by three physical factors: Airway... Show more

Pulmonary ventilation is the process of air flowing into and out of the lungs. It's also known as breathing. 

Air flows into the lungs during inhalation and out of the lungs during exhalation. This happens because of pressure differences between the atmosphere and the gases inside the lungs. 
The volume of pulmonary ventilation is the total amount of air exhaled after maximal inhalation. It's about 4800mL and varies according to age and body size. 

The ease of air passage and the amount of energy required for ventilation are influenced by three physical factors:
Airway resistance
Alveolar surface tension
Lung compliance 

Gas exchange occurs in the lungs between alveolar air and the blood of the pulmonary capillaries. For effective gas exchange to occur, alveoli must be ventilated and perfused.

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