Your skin and breathing system are losing heat to the outside, but the urine in your bladder has no direct contact with the outside and therefore cannot lose or gain heat directly from the outside.
It doesn't have to. There's a constant transfer of heat from your body, assuming ambient temperature less than 98.6°. The heat loss is from the body as a whole, and the bladder is part of that system.
[/QUOTE]Your memory is misleading you. An object (or container of liquid) will stay at a constant temp unless heat is added or removed.
A net addition of heat will raise the temp of the object, a net loss of heat will lower the temp (assuming there are no phase changes or chemical reactions). The "specific heat capacity" is the ratio of the amount of heat energy required to increase the temp of a specific mass of a substance by a specific amount.
http://en.wikipedia.org/wiki/Specific_heat_capacity[/QUOTE]
My point exactly: heat is removed from the body (as you pointed out above) through the skin and breathing. It isn't removed from the skin and lungs only, but from the body. Otherwise, you'd never get hypothermic, your skin would just freeze.
[/QUOTE]As noted above, the premise is wrong so the conclusion does not follow.
If we model the human body as 150 lb of water in an idealized (perfectly insulating, no thermal mass) container and add the appropriate amount of heat, the temp will go up 1 degree. If we use 149 lb of water, it will take 149/150 amount of heat to raise the temp 1 degree. This, however, is the energy required to
change the temp. In either case, the temp will stay constant if no heat is added or lost.
Doug[/QUOTE]
I think that's what I said. What I don't understand is why you think that no heat is lost. We lose heat anytime the ambient temp is less than body temp. The goal is to produce sufficient heat through metabolism to maintain a constant temperature. Our bodies have to produce (marginally) less heat to maintain 149 lbs. at 98.6° than to maintain 150 lbs. at 98.6°.
OK, I never did figure out how to put multiple quotes in a post.