And that's because our heart, which is found within this particular portion of the body, is actually accommodated inside the left lung. So the left lung has to use some of its space to basically accommodate our heart. And that's exactly why our left lung is slightly smaller by volume and by mass than our right lung. And that's exactly why the left lung only consists of two lobes, while our right lung consists of three different lobes. So let's begin with the left lung. We have this upper lobe, also known as our superior lobe, and we have the lower lobe of the left lung, also known as our inferior lobe.