B3.1 Gas Exchange

Question 1

Gas exchange

Answer 1

The process by which gases enter and leave the body by diffusion across gas exchange surfaces.

Question 2

What properties of gas exchange surfaces allow for efficient exchange of gases?

Answer 2

They are thin with a high surface area and are moist as gases must dissolve before diffusing across. They lie close to the capillary networks in animals with gas exchange systems.

Question 3

What are alveoli?

Answer 3

Microscopic air sacks that provide a large surface area for gas exchange. Located in the lungs of mammals.

Question 4

Where is the gas exchange surface located in mammals and other air breathing vertebrates? What are the advantages?

Answer 4

The lungs (internal), this protects them from the dry environment of the air so they can be kept moist.

Question 5

What are the ways gas exchange rates are maximised?

Answer 5

High surface area, gas exchange surfaces are only a few cells thick, concentration gradients