Joke (fun) answer : 1) inhalation 2) exhalation 3) O2 exchange 4) CO2 exchange 5) phonation (voice)
6) buoyancy (while swimming) 7) cushion (for the heart).
Real answer :
1) Gas exchange.
2) Vascular reservoir : between right and left heart.
3) Filter : embolized material gets caught at the level of the capillary radius.
4) Homestasis : heat & fluid transfer.
5) Defense barrier : foreign organisms (bacteria) and particles (dust).
6) Endocrine function : angiotensinogen gets converted to angiotensin.
7) Metabolic function : surfactant synthesis & fibrinolytic systems.
The lung is a top shelf organ that is not given its due respect in the field of medicine.
Tons of research is done on the heart and the brain and the immune system.
However, the lung is simply seen as an oxygenation / ventilation tool and possible considered
as a gateway for foreign objects from entering the inner milieu of the human body.
Great interest should also be given to the fact that the lung is a vascular reservoir.
When this pulmonary vascular reservoir is overwhelmed is when the pulmonary edema starts.
It is incredibly versatile and it should be followed by the research community as to
the result of the demise of the lung.