1.17 Gaseous Exchange

Question 1

What happens in gaseous exchange?

Answer 1

Oxygen moves from the air in the alveoli into the blood in the capillaries, while carbon dioxide moves from the blood in the capillaries into the air in the alveoli

Question 2

What is diffusion?

Answer 2

A method of movement of molecules on which they move from an area of high concentration to low concentration in an attempt to reach a balance

Question 3

What happens when you inhale? (Gaseous exchange)

Answer 3

Higher concentration in the air in the alveoli than there is in the blood, so oxygen diffuses into the blood

Higher concentration of carbon dioxide in the blood in the capillaries than there is in the air of the capillaries, so carbon dioxide molecules diffuse from the blood in the capillaries into the air in the alveoli

Question 4

Alveoli are …

Answer 4

Perfectly designed for diffusion which allows process of gaseous exchange to be efficient

Question 5

Roughly how many alveoli are there?

Answer 5

400 million, so large surface area for diffusion to take place

Question 6

What is the distance between capillaries and alveoli?

Answer 6

Short distance as they are very closely wrapped

Question 7

Is there a high blood supply to alveoli?

Answer 7

Yes, it is substantial so that lots of gas can be carried away quickly

Question 8

What happens to gaseous exchange during exercise?

Answer 8

Muscles use more oxygen, so blood returning from muscles has a lower concentration of oxygen.
This means a greater difference so more oxygen diffuses into the blood.

At the same time, there is more carbon dioxide so higher concentration.
This means greater difference so more carbon dioxide diffuses into air in the alveoli.

Overall, there is a greater level of gaseous exchange taking place during exercise, level of gaseous exchange depends on intensity of activity