Lesson 3

Question 1

What are intercostal muscles?

Answer 1

Muscles found between the rib bones.

Example: Intercostal muscles contract and relax during breathing.

Question 2

What is the diaphragm?

Answer 2

A sheet of muscle below the lungs.

Additional information: The diaphragm contracts and relaxes to change the volume of the chest cavity.

Question 3

What is the main function of the gaseous exchange system?

Answer 3

To take oxygen from the air into the lungs during inhalation and to transport oxygen to the cells of the body.

The gaseous exchange system also expels carbon dioxide from the body during exhalation.

Question 4

Where does gaseous exchange take place?

Answer 4

At the alveoli surface and between the blood and tissues.

Gaseous exchange occurs externally at the alveoli and internally between the blood and tissues.

Question 5

What occurs at the alveoli surface during gaseous exchange in the lungs?

Answer 5

Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood back into the alveoli to be exhaled.

The inhaled air has a higher oxygen concentration than the blood, leading to oxygen diffusion into the blood.