Dear student.
Lungs will not be able to expand and contract easily, if pleural membrane gets damaged.
Pleura is the outer membrane covering the lungs. It is made up of two layers. The pleural membranes are moist and slippery guarding and enclosing the lungs. The space between the two pleural membranes is called interpleural space. It is filled with air and allow the lungs to expand and contract easily.
Regards.