Gas Exchange in Insects and Fish Flashcards
What is meant by the term gas exchange?
How does gas exchange happen in fish?
They have four layers of gills on both sides of their head. The gills are made up of stacks of gill filaments and the gills filaments are covered in lamallae. When they open their mouth the water rushes over their gills and comes out of the holes on the sides of their heads. The gas exchange then happens in the blood vessels of the lamellae.
How are the gas exchange surfaces in fish adapted for gas exchange?
- The gills are made up of gill filaments, and the gill filaments are covered in lamellae, which increases the surface area for gas exchange.
- The lamellae have many blood vessels which help maintain a concentration gradient. The blood vessels are one-cell thick which decreases the diffusion distance for the gases.
- The counter-current flow of blood and water over the gills maintains the concentration gradient.
What is counter-current flow?
The blood in the gills flows in the opposite direction to the water passing over the gills, and it ensures that the concentration gradient remains constant throughout the entire length of the lamellae.
How does a gas exchange take place in insects?
Oxygen and carbon dioxide enter and leave the spiracles and move into the trachea. The trachea then branches off into the tracheoles, the gases move through those. The tracheoles deliver the oxygen straight to respiring cells.
How are the gas exchange surfaces in insects adapted for gas exchange?
- The trachea branching off into tracheoles increases the surface area for gas exchange.
- The walls of the tracheoles are one cell thick which decreases the length of diffusion pathway.
How does sufficient gas exchange occur in insects while limiting water loss?
- The insects have microscopic hairs around their spiracles that trap water and prevent it from evaporating through the spiracles.
- The spiracles open to allow gas exchange to occur and close to limit the amount of water loss.
