Ventilation in fish mindmap

  • Created by: efg150
  • Created on: 26-03-21 14:59
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  • Ventilation in Fish
    • Counter-Current System
      • Blood flows through the gill plates in one direction and water flows over in the opposite direction.
      • It maintains a large concentration gradient between the water and the blood.
        • The concentration of oxygen in the water is always higher than that in the blood.
          • So as much oxygen as possible diffuses from the water into the blood.
    • There's a lower conc. of oxyen in water than in air.
      • So fish have special adaptions to get enough of it.
    • Water, containing oxygen, enters the fish through its mouth and passes out through the gills.
    • Gills
      • Made of lots of thin branches.
        • Gill Filaments/ Primary lamellae
          • Covered in lots of tiny structures
            • Gill plates/ Secondary lamellae
              • Have lots of blood capillaries and a thin surface layer of cells to speed up diffusion.
            • Increase the surface area even more
        • Gives a big surface area for exchange of gases.
      • Each gill is supported by a gill arch.
    • How the gills are usually ventilated in bony fish
      • 1
        • The fish opens its mouth, which lowers the floor of the buccal cavity.
        • The volume of the buccal cavity increases, decreasing the pressure inside the cavity.
        • Water is then sucked in to the cavity.
      • 2
        • When the fish closes its mouth, the floor of the buccal cavity is raised again.
        • The volume inside the cavity decreases, the pressure increases, and water is forced out of the cavity across the gill filaments.
      • 3
        • Each gill is covered by a bony flap called the operculum.
        • The increase in pressure forced the operculum on each side of the head to open, allowing water to leave the gills.
      • Bony fish
        • Salmon and cod
        • They have a skeleton made of bone (not all fish do).
    • Buccal cavity
      • The space inside the mouth
    • Operculum
      • Protects the gill.


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