level: 6.3 Gas exchange in fish
Questions and Answers List
level questions: 6.3 Gas exchange in fish
| Question | Answer |
|---|---|
| Structure of fish gills | - Made up of gill filaments, stacked up - At right angles to filaments are gill lamellae - Lower concentration of oxygen in water |
| Adapations of lamellae and gill filaments | - Increases SA - Lamellae have lots of blood capillaries + thin - shorter diffusion path |
| The counter-current system for gas exchange | - Water, with oxygen, enters the mouth of the fish - Passes out of gills - Blood flows through the lamellae in 1 direction - Water flows over in the opposite direction |
| Purpose of counter-current system | - Maintains a large concen.grad. between water + blood - The concentration of oxygen in water is always higher than in the blood - So as much oxygen as possible diffuses from the water into the blood |