mechanics of breathing

Question 1

ventilation

Answer 1

the process by which air is moved into and out of the lungs
- air flows from places of higher pressure to places of lower pressure; therefore air flows in/out of lungs due to differences in air pressure

Question 2

inspiration

Answer 2

process of taking air into lungs
for air to flow into lungs, the pressure of air in the lungs must be less than the atmospheric pressure outside the body
decreasing the pressure of air is achieved by increasing volume of lungs
- diaphragm contracting, flattening and moving down *
- intercostal muscles contract, rib cage moving upwards and outwards.

Question 3

expiration

Answer 3

process of moving air out of the lungs
for air to flow out of the lungs, the pressure of air inside the lungs must be greater than the atmospheric pressure outside the body for air to flow out
increasing pressure achieved by decreasing lung volume:
- diaphragm relaxing and moving up.
- intercostal muscles relax, rib cage moves downwards.