Gas exchange in fish

Question 1

Describe the countercurrent flow system

Answer 1

1) blood flows through lamellae and water flows over lamellae in different directions
-always a higher concentration of oxygen in water than blood, hence a concentration gradient is maintained along the whole length of the lamellae → equilibrium is not met
-maximising diffusion for oxygen

Question 2

What would happen if the current was parallel?

Answer 2

-Equilibrium would be met → concentration gradient wouldn’t be maintained
-oxygen wouldn’t diffuse into blood along the whole lamellae

Question 3

What does each gill have lots of?

Answer 3

Gill filaments

Question 4

What are gill filaments covered in?

Answer 4

Lamellae

Question 5

What is the purpose of gill filaments and lamellae?

Answer 5

Gill filaments provide a large surface area and lamellae increase surface area even more

Question 6

What are the adaptations of lamellae for efficient gas exchange?

Answer 6

-Vast network of capillaries → maintains steep concentration gradient
- Thin epithelium → short diffusion pathway