Last Rat Flashcards
What is the fundamental challenge to terrestrial life?
dehydration/desiccation
What percentage of terrestrial animals are water?
50%-60%
What three things are all in equilibrium with respect to total osmolality?
plasma
interstitial fluid
intracellular fluid
Recognize that plasma and interstitial fluid are in equilibrium for _____________ , but these are not usually similar to intracellular ionic composition (remember all those Na+ and K+ pumps!)
individual ions
Differentiate between regulating your total osmolality and regulating specific ion concentrations
Specific ionic regulating: the maintenance of a constant or nearly constant concentration of an inorganic ion in the plasma
Total osmolality regulation: the maintenance of a constant or nearly constant osmotic pressure in the blood plasma
Most marine invertebrates are ___________ to seawater
isosmotic
Most marine fish are ___________ to seawater
hyposmotic
Seawater is 1 Osm = ________ mOsm
1000
Explain why osmoregulation costs energy (what is it spent on?); explain why it costs more energy in marine than freshwater fish
- The more rapidly water is taken up by osmosis, and the more rapidly ions are lost by diffusion, the more rapidly an animal will need to expend energy to counteract these processes so as to maintain a normal blood composition
- Most types of freshwater animals have far less concentrated body fluids than their ocean relatives.
- ion pumping
Explain why a reduced permeability of an animal’s skin/integument is an effective osmoregulatory strategy for any osmoregulating organism
- it reduces their rates of passive water and ion exchange and thus in reducing their energy costs of maintaining a normal blood composition
- the low permeability slows the processes that tend to bring the blood and ambient water to equilibrium
Describe and draw the relationship between an animal’s size and its evaporative water loss
The bigger the animal the greater its evaporative water loss
Describe and draw the relationship between an animal’s metabolic rate and its evaporative water loss
high metabolic rate = high evaporative water loss
The aqueous solutions (body fluids) outside cells. In animals with closed circulatory systems, subdivided into blood plasma and interstitial fluids
Extracellular fluid
- The fluids between cells in tissues. - In animals with closed circulatory systems, the fluids between cells in tissues other than blood
- Extracellular fluids other than the blood plasma
Interstitial fluid
The part of the blood that remains after blood cells are removed; the part of the blood other than cells.
Blood plasma
