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 Video. Diffusion. Diffusion is the overall movement of material from an area of higher concentration to an area of lower concentration. The difference in concentration between the two areas is called the concentration gradient; diffusion tends to continue until the concentration gradient is gone.