The tubular fluid in our body, which contains water and
other dissolved chemicals flows through the tubule. Then the substances that
are needed by our body are absorbed by the cells where these substances
included amino acid, glucose and 99% of water which goes forward to rejoin
blood in the capillaries.
If the substances don’t absorb in the tubule, these are the
wastes. On the other hand, the wastes are stashed into the tubular fluid. Then these
substances like, urea, uric acid and even excessive water make up urine.