The Controller of Storage of Fluid
It only has one defined role and that is to:
1. Removes water by Qi transformation
The Small Intestine receives digested food from the stomach and then separates this into pure Qi, which is digested and impure products that are removed. The fluid aspect of this impure substance is sent to the Bladder. The Kidneys also send their waste to the Bladder. The Bladder itself uses the heat from the Yang of the Kidneys to transform this fluid into urine and eliminate it.