Do Now
DO YOU THINK IT IS IMPORTANT TO
MAINTAIN WATER BALANCE INSIDE THE
BODY? WHY OR WHY NOT?
HINT: THINK BACK TO LESSONS ON
OSMOSIS
Osmoregulation
Osmoregulation- Regulation of water
and solute within the body.
Osmoregulation
• Regulation of water is really important
• Too much water can result in our cells swelling up
and breaking apart
• Too little results in our cells shriveling and dying.
• Various animals have different way of doing this.
No matter what the method
PROPER BALANCE MUST BE MAINTAINED.
Marine Fish: hypoosmotic
H2O continually leaves body
Less salt than
external
environment
continually
drinks
seawater
excretes salt
through gills
produces small
amts of dilute urine
Freshwater Fish: hyperosmotic
H2O continually enters body
does not
drinks
water
produces large
amts of dilute urine
More salt than
external
environment
Adaptations to Dry Environment
• Many desert animals don’t drink water
• Kangaroo rats lose so little water that
they can recover 90% of the loss from
water being produced through cellular
respiration and gain the remaining 10%
in their diet of seeds.
Dehydration in Humans
• If you are sweating too much or eating too much salt,
your body’s water content will be low.
• Brain senses this and releases more ADH—The job of
this hormone is to work with kidneys to reabsorb
water
• This results in low urine leaving your body and water
level in your body goes to normal
Hormonal Control via Negative Feedback
Too much Water
• If you drink too much, brain senses this and
produces less ADH
• Job of ADH is to hold back urine but since there
is less of ADH being produced, it will not hold
back a lot
• The result is large amount of urine leaving the
body, bringing the water level back to normal