Gas Exchange in Fish

  • Created by: Molly
  • Created on: 24-04-13 13:11
Describe the outer covering of fish?
Waterproof and gas tight. With a small surface area to volume ratio.
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Why do fish have a specialised internal gas exchange surface?
Because their body surface is not adequate enough to supply and remove their respiratory gases.
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Where are the gills located?
In the body of the fish behind the head.
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What are the gills made up of?
Gill fillaments. These are stacked up in a pile, like pages in a book.
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Where are the gill lamellae located and what is their purpose?
At right angles to the fillaments, and they increase surface area of the gills.
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What is the counter current flow in fish?
Water and blood move in opposite directions.
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Explain the counter current exchange principle?
Blood is already well loaded with oxygen and meets water which has its MAXIMUM conc of water, and so diffusion of oxygen from water to blood takes place. Blood with little or no oxygen meets water which has had most but not ALL of it's oxygen removed
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Why is countercurrent flow an efficient means of exchanging gases across the gills of fish?
Because a steady diffusion gradient is maintained over the whole length of the gill lamellae. Therefore more oxygen diffuses out of the water and in to the blood.
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Water flow over fish gills is one-way where as the flow of air in and out of the lungs is two-way. Suggest why one-way flow is an advantage to fish?
Less energy is required because the flow does not have to be reversed. And, as water is dense it is difficult to move and so this is an advantage to fish.
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Other cards in this set

Card 2

Front

Why do fish have a specialised internal gas exchange surface?

Back

Because their body surface is not adequate enough to supply and remove their respiratory gases.

Card 3

Front

Where are the gills located?

Back

Preview of the front of card 3

Card 4

Front

What are the gills made up of?

Back

Preview of the front of card 4

Card 5

Front

Where are the gill lamellae located and what is their purpose?

Back

Preview of the front of card 5
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