Gas Exchange In Fish Flashcards
What are the 3 reasons fish cannot just rely on diffusion?
-have a waterproof coating
-water is denser than air
-fish have a small surface area to volume ratio.
What is the hill covering called?
The operculum
How do fish ventillate?
-Swimming continuously or opening and closing their mouths.
What is the parallel flow method?
Water and blood flow in the same direction so a diffusion gradient is maintained for only half of the distance across the gill lamellae so only50% of the oxygen from the water diffuses into the blood as equilibrium is reached halfway across the lamellae.
What is the counter current flow?
Blood and water flow in opposite directions so a diffusion gradient is maintained across the whole distance of the gill lamellae so all oxygen can diffuse into the blood.
What ways are fish adapted for efficient diffusion?
-Have pressure changes in mouth to ventilate gills so it maintains a high diffusion gradient.
-Have many filaments and lamellae for a large surface area.
-Have a large number of capillaries so oxygen is removed from the gills quickly maintaining a high diffusion gradient.
-Thin walls on lamellae and capillaries for short diffusion pathway.
Why can young/small fish get enough oxygen without having gills?
-They will have a very small surface area to volume ratio so they can rely on diffusion alone as they have a short diffusion pathway.