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Osmoregulation
It is necessary to keep the concentration of water and solutes constant in animal bodies
- Osmoregulation: controlling the solute and water concentration in bodies
- Osmolarity: the concentration of solutes in a solution
- Excretion: getting rid of toxic waste (nitrogen)
- Animals fall into two catergories
- Osmoregulator: controls internal solute concentrations
- Most vertebrates
- Osmoconformer: does not control solutes, body is the same as the environment
- Most invertebrates
Controlling Osmotic Balance
- Stenohaline: Can not tolerate large shifts in outside osmolarity
- Euryhaline: can tolerate large shifts in outside osmolarity
- Transport epithelium: layers of specialized cells that regulate solute movements
- Tight junctions: prevent fluid leaks between transport epithelial cells
- Transport into tubular networks (countercurrent exchanges)
- Anhydrobiosis: ability to survive in a dormant state when environment dries up - Example: Tardigrades (water bears) can even survive in space
Osmotic Balance on Land
- Adaptations to reduce desiccation
- Desiccation: water lost to the environment Examples: Body coverings, nocturnal activity
- Kidneys
- Organs that are essential to mammalian water-balance and osmoregulation
- Reduce water-loss
- Excrete nitrogenous waste
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Example: Water & Ion Movement
Using the provided diagrams of freshwater and marine fish, draw arrows showing the movement of water and ions through the fish gills, skin and urine.
Freshwater:
Marine (salt water):
Practice: Vertebrate Osmoregulation
What type of osmoregulation best describes vertebrates?
Mark Yourself Question
- Grab a piece of paper and try this problem yourself.
- When you're done, check the "I have answered this question" box below.
- View the solution and report whether you got it right or wrong.
Practice: Anhydrobiosis
Describe a scenario where Anhydrobiosis would be beneficial.
Practice: Osmoregulation
Match the following terms to their correct definitions:
A.
Getting rid of toxic waste
B.
The concentration of solutes in a solution
C.
A substance dissolved into another substance
D.
Controlling the solute and water concentration in bodies
E.
The substance that dissolves another substance
Osmoregulation
Osmolarity
Excretion
Solute
Solvent