Question

Which of these things happen when we inhale air?

• A. The rib cage contracts
• B. The diaphragm becomes flattened
• C. The pressure of air inside the lungs is lowered
• D. Air moves from higher pressure to lower pressure

Answer 1

Answer: (B), (C), (D)

Air moves from higher pressure to lower pressure

When we inhale, the diaphragm contracts to flatten and hence increases the volume of the rib cage. The intercostal muscles contract so the ribs extend upwards and outwards, increasing the volume of the rib cage even further. This increase in volume lowers the pressure of air in the lungs. Then air rushes in from outside, where it is at a higher pressure.