Gas exchange in fish Flashcards
1
Q
Structure of gills
A
+Made of gill filaments and stacked up in a pile
+Gill lamella are at right angles to the filaments which increase the surface area of the gills.
+Water is taken in through the mouth and passed over the gills.
2
Q
The countercurrent exchange principle
A
Flow of water and flow of blood are in opposite directions = Countercurrent flow
Important for ensuring that the possible exchange is achieved.
∴,
1–Blood that is already well loaded with O meets H2O which has its max conc of O. ∴ diffusion from water to the blood takes place.
2–Blood with little O then meets water which has most but not all its O removed. ∴ diffusion again occurs.
∴ 80% of O in water is absorbed.