Gas Exchange in Fish and Insects
- Created by: Jasmine
- Created on: 19-02-16 20:15
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- Gas Exchange in Fish and Insects
- Gas Exchange in Fish
- Structure of Gills
- Water(plus oxygen) enters the fish through the mouth and passes out the gills
- Each gill has gill filaments which provide a large SA for exchange of gases
- Gill filaments are covered in gill plates (secondary lamellae) which also increases the SA
- Have lots of blood capillaries with a thin layer of cells to increase the rate of diffusion between water and blood
- Each gill is supported by a gill arch which have an artery and vessels for oxygenated and deoxygenated blood
- Counter Current System
- Blood flows through the gill plates in one direction whereas the blood flows in the complete opposite direction
- Water always has a slightly higher concentration of O2 when flowing next to blood which has a slightly lower concentration of O2
- This maintains the concentration gradient so equilibrium is not reaches
- Ensures that as much oxygen as possible will diffuse from the water into the blood
- Structure of Gills
- Ventilation in Fish
- 1) Fish opens its mouth to the floor of the buccal cavity
- 2) Volume of buccal cavity increases which decrease the pressure so water is sucked in
- 3) When mouth closes the buccal cavity is raised so the volume decreases and the pressure increases
- The increase in pressure is what forces the water out of the cavity and across the gill filaments
- Opperculum- a bony flap which protects the gills
- Increase in pressure forces the opperculum out and allows water to leave the gills
- Gas Exchange and Ventilation in Insects
- Insects has microscopic air filled pipes called tracheae
- Air moves in through pores called spiracles
- CO2 moves down concentration gradient and out the spiracles
- They use abdominal movements to change volume of their bodies- helps pump air in and out of spiracles
- Oxygen travels down concentration gradient to cells
- Trachaea to tracheoles to individual cells
- Tracheoles have permeable walls. They also have a fluid with the oxygen diffused into it
- Gas Exchange in Fish
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