Question

State whether the following statements are true or false.
Forceful expiration results from a forceful contraction of diaphragm.

• A. True
• B. False

Answer 1

The correct option is A True

• Forced expiration is an active process. It involves contraction of the abdominal muscles which forces the diaphragm upwards reducing the volume of the thoracic cavity.
  
• It also requires contraction of the internal intercostal muscles and innermost intercostal muscles which pull the ribs downwards. Both these actions contribute to a decreased thoracic volume and pressure is inversely proportional to volume.
  
• Therefore pressure within the lungs increases forcing the air out quicker than in normal expiration.
  

So, the correct option is 'True'.