Facts I recently found out the , after liver processes metabolites and produce urea and other byproducts , these travel along with the blood to heart and after oxygenation some of it goes to renal artery I.e to kidneys.

My questions

1Urea , in presence of water degraded into ammonia which is toxic but it does not happen as mentioned above the chance of it degrading to ammonia is high still does not happen why?

Follow up question

2.It absurd that urea instead of directly going to kidney travels through heart , is this an advantage?

P.S I don’t think it was necessary to include sources for the facts as circulatory path way is obvious.