Question

Imagine that you have been drinking a large amount of relatively pure water over the course of the day, enough to drop the osmolarity of your body fluids down from a normal level (300 mOsm) to an abnormally low level (295 mOsm). Soon after this, which of the following statements do you predict will be true?

Select ALL that will be true. Multiple answers: You can select more than one option

A Following this you will produce urine with a U/P ratio < 1.

B Following this you will produce hyperosmotic urine.

C Following this you will temporarily be less thirsty than usual.

D Following this you will temporarily generate metabolic water at a slower rate than usual.

E Following this you will temporarily lose water via evaporation across your lung epithelia at a faster rate than usual.

Answer 1

​​​​​​The correct options are A, C and E.

Explanation- when we drink too much, our plasma volume increases due to water. In this case, urine gets diluted (hyposmolar urine)because more water is excreted to correct hyposmolar plasma. So U/P ratio becomes less than 1.

Also, since there is lot of water in our blood , our thrist will be suppressed because intake of more water will increase water level even further.

This excessive amount of water is excreted in the form of evaporation by lungs.

We will produce hyposmolar urine, not hyper osmolar.

And rate of metabolic water production will be more to excrete excessive water.