Work done on Breathing (Cont/…)

During breathing there are a number of forces that play an important role in defining the work done. To simplify things, breathing can be compared to a piston that is attached by springs to the wall of the cylinder. On moving the piston down, three forces have to be overcome:

1.

elastance of the springs

Elastance of lung and chest wall

2.

frictional resistance between piston and cylinder wall

Frictional resistance within the tissues and in air movement

3.

 

inertia of the piston

Inertia of the lung and chest wall and air movement