ions and water part 1 Flashcards
what are the three homeostatic processes
osmotic regulation - osmotic pressure of fluids
ionic regulation- concentrations of specific ions
nitrogen excretion - excretion of end products of protein metabolism
strategies to meet osmotic challenges
osmoconformer- internal/external osmolarity are similar
ex. marine invertebretes
osmoregulatory- osmolarity constant regardless of environment
ex. vertebretes
strategies to meet ionic challenges
ionoconformer- exerts little control over ion profile within extracellular space
ex. marine vertebrates
ionoregulatory- control ion profile of extraceulluar space
ex. most vertebrates
how do cells control cell volume
transporting solutes in and out
water follows by osmosis
animal regulates ECF content to maintain cell volume
what is regulatory volume increase
to swell cells: importing ions, influx of water
what is regulatory volume decrease
to shrink cells: exporting ions, efflux of water
what is the purpose of epithelial tissue in ion/water balance
form boundary between animal and environment
transport of ions
how do animals reduce water flux
cover external surfaces with hydrophobic molecules
- mucus
- cornfield stratum corner with keratin
- hydrophobic matrix of keratin and lipids
features of transport epithelia
- asymmetrical distribution of transporters
- cells interconnect to form impermeable sheet of tissue
- high cell diversity
- abundant mitochondria
what are the two types epithelial transport
transcellular- water or ions moving through the membrane and out the other side
paracellular- water or small solutes moving through junctions
what are the types of epithelial transporters
Na/K ATPase
ion channels
electroneutral cotransporters
electroneutral exchangers
what cells make up the fish gill surface
chloride cells- PNA+
pavement cells- PNA+/PNA-
