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.
passive transport. The movement of a substance across a membrane with the concentration gradient. diffussion. The movement of molecules in a fluid or gas from an area of higher concentraton to an area of lower concentration. concentration gradient. Differences in concentration of a substance from one location to another.