Module 3 Section 1 - Ventilation In Fish and Insects Flashcards
What do fish use for gas exchange
A counter-current system
Where does water enter the fish and what does it pass through
Water enters through its mouth and passes through the gills
What is each gill made out of
Thin branches called gill filaments or primary lamellae
What does the gill filament/primary lamellae give
It gives a big surface area for exchange of gases
What are the gill filaments covered in
Lots of tiny structures called gill plate or secondary lamellae
What is significant about the gill plates or secondary lamellae
It increases the surface area even more
What is each gill supported by
Gill arch
What do the gill plates have a lot of
Blood capillaries and a thin surface layer of cells - this speeds up diffusion
What is it called when blood flow through the gill plates in one direction and water in the opposite direction
Counter current system
What does a counter current system maintain
A large concentration gradient. The concentration of water is always higher than that in the blood, so as much oxygen as possible diffuses from the water into the blood.
How are the fish gills ventilated
-Fish opens mouth, lowers floor of buccal cavity
-volume of buccal cavity increases
-pressure inside buccal cavity decreases
-water sucked into the cavity
What happens when the fish gills aren’t ventilated / stop ventilating
-Fish mouth closes, floor of buccal cavity is raised
-volume inside cavity decreases
-pressure inside cavity increases
-water is forced out of the cavity across gill filament
What is each gill covered by
A bony flap called the operculum
What does the increase in pressure cause the operculum to do
Forces the operculum open on each side of the head to open allowing water to leave the gills
What do insects use to exchange gases
Trachae
