OESWTE: Gas exchange in insects and fish

Question 1

What two ways are the gills in fish adapted for gas exchange?

Answer 1

• Steep concentration gradient of oxygen and carbon dioxide
• Large surface area

Question 2

Explain the fish adaptation of steep concentration of oxygen and carbon dioxide:

Answer 2

• The countercurrent flow in the lamellae allows a steep concentration gradient to be maintained so oxygen moves into the the blood along the entire length of the gill

Question 3

Explain the fish adaptation of steep concentration of oxygen and carbon dioxide:

Answer 3

• The countercurrent flow in the lamellae allows a steep concentration gradient to be maintained so oxygen moves into the the blood along the entire length of the gill

Question 4

Explain the fish adaptation of large surface area:

Answer 4

• The gills have gill fillaments which have lamellae

Question 5

Why is the countercurrent flow in fish an advantage?

Answer 5

• Means equilibrium is never reached
• Diffusion gradient will always be maintained along the entire length of the gill
• Constant flow of oxygen

Question 6

Fish have a _________ system of blood flow.

Answer 6

Counter-current

Question 7

What happens in the counter-current system in fish?

Answer 7

Blood flows through the lamellae in one direction
Water flows over the lamellae in the opposite direction.

Question 8

What is the purpose of the counter-current system in fish?

Answer 8

Water with a high oxygen concentration always flows next to blood with a lower oxygen concentration - steep concentration gradient is maintained between water and blood.