<prompt> Pleural pressure positive inEnd of inspirationEnd of expirationEnd of forced expirationSta or beginning of inspiration  <response>: During active expiration, the abdominal muscles are contracted to force up the diaphragm and the resulting pleural pressure can become positive. Positive pleural pressure may temporarily collapse the bronchi and cause limitation of air flow Ref: guyton and hall textbook of medical physiology 12 edition page number:316,317,318 