Exchange Surfaces

Question 1

What do alveoli do?

Answer 1

Maximise the diffusion of O2 and CO2 e.g. large SA, very thin walls and a good blood supply

Question 2

What is the small intestine covered in?

Answer 2

Villi- these increase the SA so digested food is absorbed much quicker into the blood. They have a very good blood supply to assist quick absorption.

Question 3

What do Guard cells do to the stomata?

Answer 3

Close them if the water is losing water faster than gaining.

Question 4

2 ways the structure of a gill is adapted for effective gas exchange?

Answer 4

Gill filaments give big SA, each gill has lamellae which further increases the SA