Gaseous exchange- In the lungs oxygen and carbon dioxide are exchanged in tiny air sacks called alveolar at the end of the bronchial tubes. The efficiency of this system is further improved by ventilation of this exchange surface and by having a correct blood supply.
The lungs are part of the breathing system which is adapted for two functions:
Ventilation- The movement of air in and out of the lungs
Gas exchange- The `swapping` of gases between the alveolar air and the blood
Mechanics of breathing- The action of breathing in and out is due to change of pressure within the thorax, in comparison with the outside. This action is also known as external respiration.
Lung volume- Lung volumes and lung capacities refer to the volume of air associated with different phases of the respiratory cycle.
Tidal Volume- This is the lung volume representing the normal volume of air displaced between normal inhalation (breathing in) and exhalation (breathing out) when extra effort is not applied within.
Residual volume- is the volume of air still remaining in the lungs after the most forcible expire (breathing out) if possible.
Vital capacity- This is the maximum amount of air a person can expel from the lungs after a maximum inhalation.
Control of breathing- Breathing continues during a sleep and usually even when a person is unconscious.
Chemical- there are chemo receptors in the brain and the heart that sense the amount of oxygen, carbon dioxide and acid present in the body.
Neural- Two types of mechanism one for voluntary breathing and one for automatic breathing.