1. B2 K EEPING H EALTHY Lesson 13: Your Kidneys

2. O BJECTIVES MUST describe how the kidneys respond to changes in blood plasma concentration SHOULD explain how alcohol and Ecstasy can disturb the water balance of the body

3. K EY W ORDS You need to be able to define the following: Blood plasma Kidneys Antidiuretic hormone (ADH)

6. T EXTBOOK A NSWERS 1)The cells would become dehydrated. 2)If an individual consumes little salt, takes in a lot of fluid, does not exercise and/or is in a cool environment. 3)The body becomes dehydrated; the body continues to produce a lot of dilute urine even though the blood plasma is too concentrated; this leads to dehydration. 4)It can cause the cells to swell; if the cells of the brain swell, this can lead to seizures and bleeding into the brain; this can cause death.

7. T EXTBOOK A NSWERS 5)ADH causes the body to retain water; so the blood plasma is diluted to the correct level; when the correct level is reached, ADH production stops. 6)Alcohol inhibits the effect of ADH; (in the absence of alcohol, if the blood plasma was becoming too concentrated and the person was becoming dehydrated, ADH would be produced to reduce the amount of water lost in urine); however, because alcohol inhibits the effects of ADH, a lot of dilute urine is still lost; leading to further dehydration; this causes a hangover.