Osmoregulation and excretionPresentation Transcript
WATER GAIN (milliliters) WATER LOSS (milliliters) by ingesting solids by ingesting liquids by metabolism in urine in feces by evaporation 6.0 0.0 54.0 60.0 850 1,400 350 2,600 13.5 2.6 43.9 60.0 1,500 200 900 2,600 KANGAROO RAT HUMAN
Maintaining water balance is tricky! These are actually two different problems – with one mechanistic solution!
2% sucrose solution 1 liter of distilled water 1 liter of 10% sucrose solution 1 liter of 2% sucrose solution Hypotonic Conditions Hypertonic Conditions Isotonic Conditions Tonicity and Osmosis
PROBLEMS salt in food FRESHWATER FISH MARINE BONY FISH s S (hyper) (hypo) W w large volume dilute urine S s (hyper) (hypo) w W PROBLEMS drinks sea water salt AT out of blood by gills small volume urine salt AT into blood by gills
LOSS GAIN H 2 O SOLUTE 1. Absorbed by gut - solid foods - beverages 2. Metabolic H 2 O 1. Urine 2. Evaporation - skin (sweat) - lungs 3. Feces 1. Absorbed by gut 2. Secreted by cells - hormones 3. Metabolism - CO 2 - ammonia - urea - uric acid 4. Respiration - O 2
Sweat - NaCl
2. Respiration - CO 2 3. Urine
US water contest radio sacks 10 The KDND 107.9 station in Sacramento sacked the hosts of its morning show and other members of staff. The show had challenged listeners to drink as much water as they could to win a Nintendo Wii video game system. One participant - Jennifer Strange - later died as a result of drinking too much water, initial tests showed. Ms Strange, 28, said she wanted to win the game - "Hold Your Wee for a Wii" game - for her children. A work colleague said Ms Strange had complained her head was hurting hours after the contest and was going home. She was found dead on Friday at her house in Rancho Cordova. The Sacramento County coroner later said preliminary autopsy findings suggested she had died of water intoxication.