[Francis Tapon]

Francis Tapon  asked the Naked Scientists:
   
Chris,

Why, when we do #2 in the loo, we must also do #1?

If that's not clear: why, when we poop, we must pee too?

Francis Tapon

What do you think?

[Eric A. Taylor]

The mussels that you use to squeeze your poo out are connected to the mussels that squeeze your bladder as well. I sometimes do #2 without #1 but only when I relax and just let things happen. However it usually doesn't take long for the smell to be noticed. Then I want to hurry things along and get out as quickly as I can.

[latebind]

I should note this is a question I have pondered many a time on the porcelain throne.

I am under the impression that the stools inside the colon apply a bit of pressure to the main pee tube. and when the stools come out the pressure on the pee tube is released and hence more pee comes out.I can usually pee a bit before a poo, but always more will come out afterwards.