The right lung is divided into three different sections, called lobes. The left lung has just two lobes. The lobes are made of sponge-like tissue that is surrounded by a membrane called pleura, which separates the lunges from the chest wall. Each lung half has its own pleura sack. This is why, when one lung is punctured, the other can go on working.
Learn Respiratory Anatomy: The Pharynx and EpiglottisHow Air Passes Through The Nose, Nasal Cavity, The Pharynx, and The Larynx
The thoracic cavity, also called the chest cavity, is a cavity of vertebrates bounded by the rib cage on the sides and top, and the diaphragm on the bottom. The chest cavity is bound by the , which connect to the ribs that surround the cavity. The thoracic cavity is actually composed of three spaces each lined with , a special film-like tissue that separates vital organs. The surround the lungs, while the surrounds and protects the heart. These tissues in the thoracic cavity can be seen in the image below