Ventilation System

Question 1

What do the intercostal muscles and diaphragm (muscle) do?

Answer 1

The lungs can’t move on their own, so the movement is done by the IM and D

Question 2

What happens during Inhaling (inspiration)

Answer 2

• External intercostal muscles contract, raising the ribcage up + out
• The diaphragm contracts + therefore moves down + becomes flatter
• The volume of thorax increases + therefore the pressure decreases
• Air enters the lungs as the thorax pressure decreases below the pressure outside the body
• Air flows to the lungs through the trachea, bronchi and then bronchioles

Question 3

What happens during exhaling (expiration)?

Answer 3

• The external intercostal muscles relax + the internal intercostal muscles contract moving the ribcage down + in
• The diaphragm relaxes + therefore moves upwards + becomes dome shaped
• The abdominal muscles contract pushing the diaphragm up
• the volume of thorax decreases + therefore the pressure increases.
• Air moves out of the lungs through bronchioles, bronchi and then the trachea.

Question 4

What is ventilation?

Answer 4

The exchange of gases between the lungs + air

Question 5

What is the thorax?

Answer 5

The empty space in lungs, the space between the neck + diaphragm