The lungs perform gas exchange, taking in oxygen and releasing carbon dioxide. Their physical placement within the body directly influences their function. These spongy, expandable structures are housed within a protective framework, allowing them to expand and contract.
Where Your Lungs Reside
Your lungs are primarily located within the thoracic cavity, often referred to as the chest cavity. This protective space extends from the base of your neck down to the diaphragm, a large muscle separating the chest from the abdomen. Each lung is enclosed by a double-layered membrane called the pleura, with a thin layer of lubricating fluid between its layers. This fluid allows the lungs to glide smoothly against the inner chest wall during breathing, minimizing friction.
The upper part of each lung, known as the apex, extends slightly above the first rib and collarbone area. Horizontally, the lungs fill much of the chest cavity, flanked by the rib cage which provides protection. The lower surface of the lungs, called the base, rests directly upon the dome-shaped diaphragm. This lower boundary is approximately at the level of the sixth rib in the front and the tenth rib in the back.
While there are two lungs, they are not symmetrical. The right lung is generally larger and wider, divided into three sections called lobes. In contrast, the left lung is slightly smaller and has only two lobes. This size difference in the left lung accommodates the heart, which is positioned predominantly on the left side of the chest, creating a concavity known as the cardiac notch.
How Lungs Use Their Space
The lungs utilize the space within the thoracic cavity during breathing, which involves coordinated muscle actions. Inhalation is an active process driven primarily by the contraction of the diaphragm. When the diaphragm contracts, it flattens and moves downward, effectively increasing the vertical volume of the chest cavity.
Simultaneously, the external intercostal muscles, located between your ribs, contract and pull the rib cage upward and outward. This combined action further expands the thoracic cavity in all directions. As chest cavity volume increases, pressure inside the lungs drops below atmospheric pressure. This pressure difference creates a vacuum effect, causing air to rush into the lungs and expand them.
Exhalation is typically a passive process during quiet breathing. The diaphragm and external intercostal muscles relax, allowing the diaphragm to return to its dome shape and the rib cage to move inward and downward. This reduction in thoracic cavity volume increases the pressure within the lungs, expelling air. The natural elasticity of the lung tissue also contributes significantly to this recoil action, allowing the lungs to return to their resting size.