Download Osmoregulation and Excretion

Osmoregulation and Excretion
Maintaining balance of water
• Osmoregulation
– Regulate solute concentrations
– Balance the gain and loss of water
• Excretion
– The disposal of mostly nitrogenous waste
products of metabolism
How does the solvent move through a permeable membrane?
A hypo
B hyper
Salt 20%
Salt 70%
Water 80%
Water 30%
Osmosis is the spontaneous net movement of solvent molecules through
a partially permeable membrane into a region of higher solute concentration
(hypo to hyperosmotic solution), in the direction that tends to equalize
solute concentrations (Isoosmotic sol.)on two sides by osmotic pressure.
Get the answer!
Then in case of fish, what do you think?
Saltwater fish
Freshwater fish
Saltwater fish
Hypoosmotic solution
Freshwater fish
Hyperosmotic solution
Osmoregulation
Kidney play a large role by regulating the amount of water reabsorbed
from glomerular filtrate in kidney tubules
Physiology of osmoregulation and excretion
Osmoregulation is controlled by…
Regulation of
blood volume
& pressure
Renin-angiotensin system
Angiotensin II:
Increases Na+ and water reabsorption.
Causes vasoconstriction to increase blood pressure.
Aldosterone:
Increases Na+ and
water reabsorption
BP decreased;
JG cell produce
Renin
Regulation of
ECF osmolarity
and volume
sense the Na conc.
of the blood.
If the Na conc. of the blood is high, the
osmoreceptors secrete ADH. If the Na
conc. of the blood is low, they don't
secrete ADH.
Excretory process
• The process of separation and elimination of
waste products (esp. nitrogenous waste)
• Waste products are formed due to catabolism
of amino acid, glucose, glycerol, fatty acids.
• Maintain homeostasis within organism and
prevent damage to the cell body.
The elimination of waste products
Function of kidney
I.
II.