Why a Chest Tube is Placed. A chest tube is placed for a variety of reasons. One reason, as you mentioned, is to help the lung re-inflate when someone has a collapsed lung, also known as a pneumothorax. In that circumstance, a chest tube is inserted along the side of the ribs to allow the lung to reinflate.
A. Osmosis is the passive movement of water from an area high in water concentration, across a semi-permeable membrane, to an area low in water concentration.
Bulk Flow: Filtration and Reabsorption Bulk flow is a passive process in which large numbers of ions, molecules, or particles in a fluid move together in the same direction. The substances move at rates far greater than can be accounted for by diffusion alone.