Chapter 39.1- Water and electrolyte balance Flashcards
What is osmosis?
the movement of water from a place of low solute to higher solute
Is water a solute or a solvent?
Water is a solvent
What is the difference between a semipermeable membrane and a selectively permeable membrane?
Semipermeable: allows water the pass through but not other solutes
Selectively permeable membrane: cell membranes allows certain molecules to pass through but not all
How does water pass through cell membranes?
Through channels where water can flow called aquaporins
What is osmatic pressure?
it is the pressure needed to prevent water from moving by osmosis across a selectively permeable membrane.
What is the relationship between solute concentration and osmatic pressure?
the higher the concentration of solute the higher the osmatic pressure of water
What are the two ways that water movement can be prevented in a cell?
Osmatic pressure : pressure
Hydrostastic pressure: gravity + stiffness of container walls
When is equilibrium reached during osmosis?
Equilibrim is reached during osmosis when the osmatic pressure equals the amount of hydrostatic pressure
What is osmoregulation?
Osmoregulation is the regulation of water in order to keep internal fluids from being too diluted or too concentrated.
Osmoregulation is achieved by the control of
solutes especially electrolytes
How does freshwater fish and terrestrial animals gain water vs lose water?
Gain: by drinking water with low solute concentration
(hypotonic solutions) food, cellular respiration,
freshwater fishes through their gills
Lose: Animal through urine and feces. Sweating and lung evaporation. Salt water fishes through their gills.
How do animals, marine animals and freshwater fishes gain vs electrolytes?
Gain: Animals gain electrolytes through their food and marine animals through salt water
Lost: in urine and feces. Or in gills
What are osomoconformers?
They keep their cells internal fluids as the same concentration of the enviorment. They go with the flow.
What are osmoregulators ?
osmoregulators are animals that maintain the cell at a lower/higher concentration than the surrounding environment.
What are the characteristics of osmoregulators? and what organisms are osomegulators?
- they use alot of energy in order to maintain homeostasis
- Because of homeostasis they can live in diverse environments
- most vertebrates
- freshwater fishes and terrestrial
What are some characteristics of osomoconformers ? What organisms are osomoconformers?
- most invertebrates (sea stars, lobsters, mussels)
- they tend to live in enviorments where the concentration of water is stable such as sea water.
- cells are actively pumping sodium out and potassium in
How does marine fishes osmoregulate?
Marine fishes osmoregulate through actively secreting salt through gills, feces, and energy pumping ions
What are the challenges marine fishes face as osmoregulators?
The fish is hypertonic compared to the salt water in the environment and therefore loses a lot of water. And needs to pump out salt content.
Salt water ions move into the fish and water moves out.
How does freshwater fishes osmoregulate?
- they do not drink water bc they have so much water
- they produced diluted urine
- they maintain high concentrations of electrolytes
-they use their gills to pump chloride and sodium into the cells
What are some challenges that freshwater fishes that osomoregulate face?
they are hypertonic to the enviorment so the water enters their cell and their salt ions get secreted
How does amphibians deal with excess salt? how do land animals intake water
sea turtles iguanas ands sea birds have salt glands
- land animals produce concentrated urine and drink water
How does a salt gland work?
- it actively pumps ions from the blood into cells that make up the glands.
- excrets salt through the gland and naval cavity
- it allows birds and reptiles to gain netw water by drinking sea water
