EXPIRATION

• PROCESS OF EXPIRATION?

  1. External intercostal muscles relax
  2. Internal intercostal muscles contract, pulling ribs down and inwards
  3. Diaphragm relaxes, causing it to move up and dome
  4. Lung air pressure increases
  5. Lung volume decreases
  6. Air moves out of lungs as thorax pressure is greater than atmospheric pressure
• WHAT HAPPENS TO EXTERNAL INTERCOSTAL MUSCLES IN EXPIRATION?

  relax
• WHAT HAPPENS TO INTERNAL INTERCOSTAL MUSCLES IN EXPIRATION?

  contract
• WHAT HAPPENS TO RIBS IN EXPIRATION?

  pulled down and inwards
• WHAT HAPPENS TO DIAPHRAGM IN EXPIRATION?

  relaxes causing it to move up and dome
• WHAT HAPPENS TO LUNG AIR PRESSURE IN EXPIRATION?

  increases
• WHAT HAPPENS TO LUNG VOLUME IN EXPIRATION?

  decreases