6.3 - Gas exchange in fish

• What size SA:V do fish have ?

  Small, they are relatively large
• What are gills made up of ?

  Gill filaments
• What structure on gill filaments increases their surface area ?

  Gill lamellae
• What's the name of the process in which the flow of water over the gill lamellae is opposite to the flow of blood ?

  Countercurrent flow
• How does the countercurrent flow ensure diffusion of oxygen into the blood can occur ?

  Maintains a difference in oxygen concentration and a diffusion gradient across the lamellae