Pathway of air

Question 1

What is the respiratory system responsible for?

Answer 1

Breathing and gaseous exchange

Question 2

Describe the pathway of air.

Answer 2

1) Air is travelled through the mouth and nasal passages
2) It then passes through the trachea into one of the two bronchi’s into one of the lungs
3) After passing through many bronchioles, it finally arrives into some of the millions of tiny sacks called the alveoli
4) This is where gas exchange takes place - oxygen passes out of the air into the blood, and carbon dioxide passes out of the blood into the air in the alveoli

Question 3

When inhalation occurs, what happens?

Answer 3

1) Diaphragm contracts and flattens
2) Intercostal muscles contract lifting the ribs up and out
3) Space inside the lungs increases and therefore pressure decreases
4) Pressure outside the body is now greater than the pressure inside, causing air to rush in.

Question 4

When exhalation occurs, what happens?

Answer 4

1) Diaphragm relaxes returning to its dome shape
2) Intercostal muscles relax
3) Space inside the lungs decreases and therefore pressure increases
4) The pressure inside the body is now greater than the pressure outside, forcing air out.