gas exchange in fish Flashcards
why would lungs not work for water dwelling animals
use to much energy to move water in and out of them
gas exchange site of fish
gills
how does water move through gills
over them in one direction only- more effective and efficient in energy for fast moving active water animals
fish with high oxygen demand
bony fish has high oxygen demands because they are very active
why cant their scaly external conduct gas exchange
because the external is not permeable to gases
evolved gas exchange of fish
works well in high viscosity and slow rate of oxygen found in water
adaptations of gills for gas exchange
-large surface area
-good blood supply to maintain conc gradients
-thin walls for short diffusion
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protection of gills of bony fish
contained in gill cavity and covered by protective bony flap operculum
operculum
protective bony flap
gill filaments
occur in large stacks
features of gill filaments
need water to keep them apart and for exposing large surface area for gas exchange
main site of gas exchange
gill lamellae
features of gill lamellae
-rich blood supply
give gills filaments for large surface area
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counter current exchange example
blood leaving gulls flows in opposite direction to incoming water- most effective exchange of gases
what fish dont have operculum
cartilaginous fish
why dont cartilaginous fish have operculum
they have to swim all the time to keep water flowing over mouths and over gills
system with operculum with bony fish
evolved do they can ventilate gills what they are not moving
counter current exchange system for max efficiency
-maintains steeper gradient
-more than if blood and water flowed in same place
-more gas exchange 80 percent oxygen in bony fish
overlapping gill filaments for max efficiency
tips of adjacent gill filaments overlap, increasing resistance of flow of water.
slows down flow of water over gills so more time for exchange to happen
