9.4 Water Balance Flashcards
Osmotic pressure
The pressure that results from a difference in solute concen. btwn the 2 sides of a selectively permeable membrane
Hyperosmotic
The property of the solution on one side of a selectively permeable membrane that has the lower concen. of water
Hypoosmotic
Property of solution on 1 side of a selectively permeable membrane that has the higher concen. of water
Isoosmotic
The property of 2 solutions that have equal water concen.
Osmoregulation
Process of actively regulating the osmostic pressure of bodily fluids/cells
Recap:
Osmotic pressure: results from difference in
solute concentration on two sides of membrane
Osmoregulation: actively regulating water
balance/osmotic pressure of bodily fluids and
cells
Excretion
Certain ions, toxins, and nitrogenous compounds must be eliminated
- Water needed for terrestrial organisms to dissolve solutes and then excrete
- Ionic/pH balance and osmotic concen. are regulated
- Involves kidneys/bladder
Deamination
A.A contains amino groups– with nitrogen
- Converted into ammonia which is toxic
- Must be dilute; 0.005mg is lethal
- Fish can remove ammonia directly into environ. bcuz of water surrounding them
Humans/terrestrial organisms need water to dilute ammonia for storage
Until excretion
Urea
100000xs less toxic than ammonia
Bicarbonate + ammonia in liver
–> urea
ADH
- A hormone produced in
hypothalamus, released
by pituitary - Causes kidneys to
increase water absorption - More ADH = more
concentrated urine - Conserves water
Antidiuretic Hormone
- Diuretic = coffee =
makes you urinate - ADH regulates
osmotic pressure
ADH cont’d 2.0
- Hypothalamus
shrinks—pituitary
releases more ADH - ADH makes kidney more
permeable to water - :. body retains more
water
ADH cont’d
- Osmoreceptors detect water loss
- Less water intake = more concentrated blood
- Water osmoses out of cells into blood (to dilute
the blood)
