1.4 Gas Exchange In the Lungs

Question 1

Why do large complex organisms have special exchange surfaces?

Answer 1

To obtain all the food and oxygen they need efficiently

Question 2

What are the bronchi?

Answer 2

The tubes from the trachea into the lungs

Question 3

What are bronchioles?

Answer 3

The air tubes within the lungs

Question 4

What are the alveoli?

Answer 4

Air sacs at the ends of the bronchioles

Question 5

Name 4 adaptations of the alveoli that make them very efficient at exchanging materials in the lungs

Answer 5

• only one cell thick, so the materials don’t have to travel far
• network of fine capillaries, so the gas can pass easily
• moist, so the gas can dissolve easily
• large combines surface area in the lungs, so more diffusion can happen and more gas is exchanged per breath

Question 6

What surface do the lungs contain?

Answer 6

The gaseous exchange surface

Question 7

How does gas exchange in the lungs happen?

Answer 7

1. The oxygen is breathed in, moves into an alveolus and moves by diffusion into the bloodstream
2. The bloodstream is constantly moving so the concentration gradient is maintained
3. The carbon dioxide passes out of the bloodstream into the alveolus via diffusion and is breathed out

Question 8

How can we maximise the concentration gradient?

Answer 8

Breathing, so the diffusion in the lungs can happen constantly

Question 9

How is the lungs surface area so huge?

Answer 9

It has lots of fine capillaries

Question 10

How does ventilation of the lungs help maximise gas exchange?

Answer 10

Ventilation of the lungs, along with the movement of the blood, makes sure we maintain a steep concentration gradient so more diffusion can happen

Question 11

What are solutes?

Answer 11

Soluble food materials absorbed by the intestine