Gas Exchange In Insects And Fish Flashcards
What is Surface area: volume ratio?
The important relationship between the surface area of a biological unit such as a cell or a whole animal, and its overall volume, which affects many aspects of its biochemistry. As the size of the unit increases, its surface area grows relatively more slowly than its volume.
What is an Exchange surface?
Surfaces across which substances could be transferred. To allow exchange to be efficient, surfaces will often have a large surface area:volume ratio, be very thin and selectively permeable. There will also often be movement of the environmental medium and a transport system to ensure the movement of the internal medium.
What is a Concentration gradient?
The difference between the concentration of a gas or substance inside and outside of the cell. The steeper the concentration gradient, the faster the rate of diffusion.
What is the tracheae?
A large internal network of tubes in insects with supported rings to prevent them collapsing.
What are the tracheoles?
These tubes extend from the tracheae and extend throughout all the body tissues of the insect to allow atmospheric air to be brought directly to respiring tissues.
What is a spiracle?
Tiny pores that allow gases to enter and leave the tracheae (and water vapour to leave as well). They are opened and closed by a valve.
What is a gill?
Located within the body of the fish, behind the head.
What are the gill filaments?
Make up the gills of a fish – they are stacked up in a pile.
What are the gill lamellae?
At right angle to gill filaments, which increase the surface area of the gills.
What is countercurrent flow?
Describes how the flow of water over the fill lamellae and the flow of blood within them are in opposite directions. Allows a diffusion gradient to be maintained all the way across the gill lamellae.
