Gas Exchange In Fish Flashcards
What process is slower in water than in air?
Diffusion.
What do bony fish have a high demand of?
Oxygen as they are large active animals with a high metabolic rate.
What is there a lower concentration of in water than in air?
Oxygen
What is the gas exchange surface in fish?
Gills
What are the thin plates called that make up the gills?
Gill filaments
OR
Primary lamellae
What is significant about the gill filaments?
They have a large surface area so gas exchange happens over a bigger area…..so diffusion of gases is quicker.
What are the gill filaments covered in?
Lots of tiny Gill plates OR secondary lamellae.
What do the secondary lamellae provide for the gills?
An even bigger surface area for gas exchange.
What is each gill supported by?
A gill arch.
What 2 features do the gill plates have that speeds up diffusion between the water and blood?
1) A thin layer of cells
2) Lots of blood capillaries
What is a counter-current system?
Blood flows through the gills in one way and water flows over the gills in the opposite direction.
Why is the counter-current system more efficient?
It allows water with a high oxygen concentration to always flow next to blood with a low oxygen concentration.
This means a STEEP concentration gradient is maintained and never reaches equilibrium.
What 5 adaptations of the gaseous exchange system in fish make it EFFECTIVE?
1) Large Surface Area {more diffusion}
2) Rich Blood Supply {steep conc gradient}
3) Thin Layers {short diffusion distance}
4) Overlapping Gill Filaments (increases resistance and slows flow of water over gills) {more time for diffusion}
5) Opposite flow of blood and water (counter-current flow) {steep conc gradient}
What is a parallel system?
Where the blood in gills and water flowing over gills flow in the same direction.
Why is a parallel system not as effective as the counter-current system?
Initially there is a steep conc gradient but eventually equilibrium occurs between the blood and water so no more net movement of gases occurs.
