Gas Exchange In Fish Flashcards
Is there a higher concentration of oxygen in water or air
Air has a higher concentration of oxygen than water
What do bony fish have? What does this do
Bony fish have an operculum. This helps to maintain a flow of water even when stationary
Do cartilaginous fish have an operculum? What do they have to do
No, they have to keep moving in order to have a continuous flow of water
Do bony fish or cartilaginous fish have an operculum
Bony
How does gas exchange work in fish
Water comes in to the fish via the mouth, fish then pump the water over the gills
What are gills made of
Lots of thin plates called filaments
What are filaments covered in? What does this do
Structures called lamellae.
This increases the surface area of the gills
Apart from filaments and lamellae, what else do gills have? What does this do
Lots of capillaries and a thin membrane to speed up diffusion
How are fish gills adapted for gas exchange
Filaments are covered in lamellae for increased surface area for gas exchange
There are lots of capillaries speed up diffusion
Thin lamellae wall gives a short diffusion distance between water and blood, speeding it up
What is a countercurrent system? What does this do
The blood system in the lamellae is arranged so that water flows in the opposite direction to the blood flow in the capillaries. This makes gas exchange more efficient
What does water and blood flowing in opposite directions mean
It means diffusion will always occur DOWN a concentration gradient so the water will always have a higher concentration of oxygen than the blood no matter its position in the gills
How does countercurrent flow work and what is its purpose
Countercurrent flow is where the water and blood flow in opposite directions through the lamellae
This means the oxygen concentration is always higher in the water than in the blood near
So a concentration gradient of oxygen between the water and the blood is always maintained for diffusion along the whole length of the lamellae
What is parallel flow
Where water and blood flow in the same direction along the gill plate
What happens if parallel flow happens
Equilibrium would be reached so oxygen wouldn’t diffuse into the blood along the whole gill plate
