Lungs in humans: Two reddish sponge-like lungs are situated in the thorax above the diaphragm. Each conical lung is enclosed in a double-layered membrane sac called the pleura. The right and left lungs are divided into 3 and 2 lobes. In each lung, the primary bronchi divide and subdivide into many terminal bronchioles. The exchange of gases takes place in the lungs.