Mechanics Of Breathing

Question 1

Inspiration

Answer 1

Thoracic cavity expands - up and out (intercostal muscles contract)
Diaphragm moves downwards - flattens (contracts)

For air to travel into your lungs, pressure inside the lungs must be lower than the atmosphere

Volume increases and Pressure decreases

Question 2

Expiration

Answer 2

Thoracic cavity decreases in volume - down and in (intercostal muscles relaxes
Diaphragm goes back into the arch shape (relaxes)

Pressure in the lung need to be higher than atmosphere
Pressure = High to low