Gas Exchange In Fish Flashcards
Gas exchange in fish?
Water is more dense than air, the concentration of oxygen in the water is lower than in the air. The oxygen diffuses more slowly in water than in airs. Fish as complex large organisms therefore have a small SA:V ratio. Fish are waterproof therefore are gas tight, they are cold blooded. The properties of water compared to airs mean that the SA for gas exchange and the ventilation mechanism for fish need to be different the from mammals.
The structure of fish?
Gas exchange occurs in the gills which are supported by a gill bar/arch. Gill bar/arches are made of bone or cartilage, the space between the Gill bar/arches is called the Gill slit. Each Gill has 2 rows of filaments which are covered in folds called lamellae.
How does gas exchange occur in fish?
Via diffusion
What ensure efficient diffusion in fish?
- in the lamellae, the distance between the water and blood is 5 micrometers which create a short diffusion pathway.
- gills are made of many filaments and lamellae which causes a large SA:V ratio.
- gills have an extensive network of blood capillaries which creates a concentration gradient.
- a counter current flow system which maximises gas exchange as oxygen and carbon dioxide flow in opposite directions further maintaining a concentration gradient.
There is less oxygen in water with high temperature.
