Chapter 11 Part 1 Flashcards
Gas exchange occurs primarily through
passive diffusion
Pass Diff: Molecules move from high concentration to
low
To maxm. gas exch.: Organisms prov. large thin SA to envr./maint. steep partial press. gradient that favors…
entry of O2 and elimination of CO2
Terrestrial/Aquatic animals face diff. chall. in performing…
gas exchange
Ventilation= active process of moving respr. medium over
exchange surface
Water is denser-requires more energy to move
across GEO’s
Solubility of gases differs:
Air(more constant)/Water (variable)
Water (variable) depends on:
temp of water, chemistry of gas, partial press. in air, presence of other diss. subst.
Oxygen Exch.: The Problem-
Water has less O2 than air
Is heavier/thicker, harder to move
Common range of O2:
three to ten ppm
“Warm water fishes” (carp, crappie, catfish) live in…
5 ppm low numbr. cause of temp
“Cold water fishes” (salmon, steelhead trout, sturgeon) live in…
ten ppm
Solut. to water breathing:
Low metabolism/high SA of gas exch. and Gill structure
Undirectional-in most fish gills; movem. of water across…
gill curtain occurs in one direction
Bidirectional (tidal)-lung ventilation; air enters/exits through…
same channels
