The alveoli branch off from the bronchioles and bronchi that connect to the trachea and allow air to pass into the lungs. The interior of the lung contains the alveoli, where gas exchange occurs. Interior of the thoracic cavity: This is a transverse view of the thoracic cavity, showing the pleural cavity and the major structures around the lungs. The fluid inside the pleural cavity protects against irritation during inhalation as well. The pleural cavity is the fluid-filled space between the parietal and visceral pleura, and provides room for the lung to expand during inhalation. The pleura contain two layers, the outer parietal pleura (attached to the thoracic cavity), and the inner visceral pleura (covers the lungs). The outer layer of the lungs are the pleura, a type of mesothelium (membrane tissue) that surrounds the lung and attaches it to the thoracic cavity. The right lung is larger than the left lung, and the left lung contains the cardiac notch, a concave impression that the heart lies against. The diaphragm, a sheet of skeletal muscle that lies beneath the lungs, plays an important role in inhalation. The base is curved inward to allow it to rest on the diaphragm. The lungs are cone-shaped-the apex refers to the top of the lung, while the base refers to the bottom of the lung.

The vertebral column is posteriorly attached to the ribcage and the lungs. The rib cage is a structure of bones that surrounds and protects the thoracic cavity, with 12 ribs protecting each of the two lungs. The lungs are found in the thoracic cavity, and extend laterally into the right and left halves around the heart. The human lungs flank the heart and great vessels in the chest cavity: The human lungs flank the heart and great vessels in the chest cavity.

Shunt vs dead space question