The Process of Gas Exchange

Question 1

What happens first during gas exchange?

Answer 1

The artery to the lungs brings deoxygenated blood to the capillaries.

Question 2

What happens when deoxygenated blood enters the capillaries?

Answer 2

Carbon dioxide diffuses from the high concentration in the blood to the lower concentration in the air in the alveolus.

Question 3

What makes the diffusion of gases easier during gas exchange?

Answer 3

• Alveolus wall is one cell thick
• Capillary wall is one cell thick
• Inside of alveolus is lined with a film of moisture

Question 4

What happens during the diffusion of carbon dioxide?

Answer 4

Carbon dioxide diffuses from the higher concentration in the blood to the lower concentration in the air in the alveolus.

CO2 dissolved in plasma diffuses into the alveolus. Carbaminohaemoglobin breaks down into haemoglobin and carbon dioxide which also diffuses into the alveolus. Hydrogen and bicarbonate ions combine to form carbonic acid which is broken down under enzyme action into water and carbon dioxide, which also diffuses.

Question 5

What happens during the diffusion of oxygen?

Answer 5

Oxygenated blood leaves the capillaries of the alveolus is taken to the heart in the veins from the lungs.

Question 6

What happens when the oxygenated blood is pumped to the body?

Answer 6

The RBCs flow through the capillaries between the body cells, they give up their oxygen, which diffuses into the tissue fluid and then into the cells

Question 7

What is gas exchange?

Answer 7

The movement of carbon dioxide and oxygen.

Oxygen from inhaled air in the lungs moves into the bloodstream.

At the same time, carbon dioxide, a waste product, diffuses from the blood into the lungs to be exhaled.

It is a passive process driven by diffusion, where gases move from areas of high concentration to areas of low concentration without requiring energy.