Lecture 9 - Water balance

Question 1

Osmolarity is ….. of volume

Answer 1

indpendent

Question 2

What is the obligatory water loss and how much is it?

Answer 2

we have to pee because we have to get rid of waste. It is about 500 ml a day.

Question 3

How high can water loss be?

Answer 3

18L per day

Question 4

What is insensible water loss and where/how much?

Answer 4

water loss that you do not see or think about like skin or lungs. Exercise can increase it and it can be as hiigh as 3.5L an hour from skin.

Question 5

It is …. to manage osmolarity than volume

Answer 5

harder

Question 6

under normal circumstances osmotic pressure … and …. is equal

Answer 6

inside and outside cell

Question 7

What is the range for normal osmolarity?

Answer 7

280-300 mOsm/L

Question 8

Wht are osmoreceptors?

Answer 8

They sense the plasma osmolarity and specifically the ECF osmolarity

Question 9

What happens over 290 mOsm/L?

Answer 9

triggering the release of ADH

Question 10

what happens to cells when ECF osmolarity increases?

Answer 10

cells shrink and the release of ADH makes thebody stop losing water. ADH also goes to thirst center to increase thirst.

Question 11

What iis ADH and why is it so useful?

Answer 11

it is a nonapeptide that is broken down by the liver. It is rapidly secreted and rapidly cleared by the kideny. Hence, very easy to contol and has minute to minute regulation of Posm.