How do lungs work on the tissue level, describe the function of lung tissue

The name for the lung tissue (ik its not what ur asking im getting to that) is also known as pleura, its a thin layer of tissue that goes over the lungs and it helps to know what its called. 

now to answer ur actual question, the pleura applies preasure to the lungs which allows us free movement and it helps us breathe better, in a way its like a shield almost. the pleura is ,like mentioned before, a thin layer over the lungs. 

hope this helps :) have a nice day

Gravitational force i believe