Oxygen is breathed in and carbon dioxide is breathed out as it is deadly to humans. Too much carbon dioxide breathed in will cause brain damage and eventually death.
Air tends to flow into the lungs when thoracic volume increases and pressure decreases. When the opposite is true, air leaves the lungs.
That is called the Trachea.
The movement of air on and out the lungs is called respiration. The movement of air into the lungs is called inhalation (inspiration). The movement of air out of the lungs is called exhalation (expiration).
The term for moving muscles in order to make air flow into and out of the lungs is breathing. The main muscle that moves is the diaphragm, which sits just below the lungs and causes air to flow in and out as it contracts and expands.
There are no muscles in the lungs that help inhale or exhale, this is the job of the diaphragm.
Since the volume of the lungs increases, the intrathotacic pressure decreases, and air moves into the lungs.
The air left in your lungs after exhaling is called "Expiratory Reserve".
The flow of blood from the heart to the lungs and back to the heart is called pulmonary circulation.
when pressure inside the lungs is lower then outer atmosphere
Inhalation. Breathing.
When air passes through your lungs it is called respiration.
After oxygen is inhaled, air containing carbon dioxide (waste for humans, though nutrient for plants) is reflexively exhaled. It is in this manner that air tends to flow out of the lungs.