Gas Exchange In Fish Flashcards
Why is the outer covering gas tight?
Because it is waterproof.
What is the specialised internal gas exchange surface in fish?
Gills
Where are the gills located?
Behind the head.
What are gills made up of?
Gill filaments.
How are the gill filaments stacked?
They are stacked up in a pile.
What can be found at right angles to the filaments?
Gill lamellae
What do gill lamellae do?
Increase the surface area of the gills.
Where does the water travel in the fish?
Through the mouth, over the gills and then out through an opening on each side of the body.
What is countercurrent flow?
This is where the flow of water over the gill lamellae and the flow of blood within them are in opposite directions.
What would happen if the water and blood flowed in the same direction?
Far less gas exchange would take place.
Where do the blood and water flow over?
The gill lamellae.
What are the two benefits of the countercurrent exchange principle?
Blood that is already well loaded with oxygen meets water, which has its maximum concentration of oxygen. Therefore diffusion of oxygen from the water to the blood takes place.
Blood with little oxygen and it meets water which has had most, but not all, of its oxygen removed. Again, diffusion of oxygen from the water to blood takes place.
What happens as a result of countercurrent exchange?
The diffusion gradient for oxygen uptake is maintained across the entire width of the gill lamellae.
What would the diffusion gradient be like in parallel flow?
Only 50% of the available oxygen would be absorbed by the blood.
What is parallel flow?
This is where the blood and the water flow in the same direction.
