How do marine teleosts actively get rid of salts?
- Na+/ K+ ATPase builds huge Na+ gradient within chloride cell
- Cl- transported using Na+ gradient
- Cl- builds up and diffuses out
- Na+ follows Cl- change by sneaking through leaky tight cell junctions
How do freshwater teleosts actively take up salt?
- Lots of mitochonria and Na+/ K+ ATPase
- Cell cytoplasm very low in Na+ and Cl-
- Apical membranes have ion pumps to pump ions IN
- Cell junctions dont leak
How do freshwater teleosts stop gaining too much water?
1) Large amounts of dilute urine
2) Active take up of salt through gills
What are 3 ways marine teleosts keep their body fluids at the correct concentration?
- Actively remove salt from their bodies
- Small amounts of concentrated urine
- A lot of mitochondria in gills to expel salt by active transport
What is the difference between osmoregulators and osmoconformers?
Osmoreguators: as osmolarity of environment changes the osmolanty of body fluids is regulated within a small range
Osmoconformers: concentration of body fluids changes with the environment
What is hyperosmotic, hypoosmotic and isomotic?
Hyperosmotic = a higher concentration of solutes within it (saltwater)
Hypoosmotic= a lower concentration of solutes within it (freshwater)
Isomotic= equal concentration, no net movement
What is Tonicity and 2 things it depends on?
The effect of a solution on a cells volume
Depends on:
1) Solutes
2) Membrane permeability
What is the equation for osmolasty and what is it measured in?
number of particles per molecule of solute x moles/ litres
Measured in osmoles/ litre
What is osmolarity?
Measure of the osmotic pressure exerted by a solution across a perfect semi permeable membrane compared to pure water
What are the 5 things that influence the rate of passive movement? (solutes)
1) Temperature (higher=faster)
2) Size of particles (smaller=faster)
3) Electrical change of ion (can prevent passage)
4) Concentration gradient
What is osmoregulation
- Process that balances the uptake and loss of water
- Homeostatic control
