When you take a breath, air travels through your windpipe (trachea) and is divided through two smaller tubes (bronchi) - one to the left lung and one to the right. This airway then divides repeatedly into smaller parts leading to millions of miniature air sacs (alveoli).
These alveoli look like tiny bunches of grapes covered in a fine mesh of blood vessels, called capillaries. The thin walls of these capillaries transfer oxygen from the alveoli to your blood - transporting this vital oxygen-rich blood around the body. Your alveoli are so numerous that your body does not need to use them all to breathe efficiently, meaning that the lung has spare resources if it becomes damaged.
Behind the trachea is a second tube (the esophagus) that transports food. To control the path of food and air, the tubes have a control gateway (the epiglottis) which prevents food or liquid from entering the trachea. If your epiglottis fails to do its job and allows food into your windpipe, it causes you to cough or choke.
Below your lungs is a muscle called the diaphragm - a major part of the breathing mechanism. The diaphragm and the intercostal muscles between your ribs work together to provide a space into which your lungs can expand, drawing air through your nose or mouth in the process.
Your lungs other parts
The airways leading to your lungs are specially designed to keep air passages moist and aid in intercepting dust and bacteria. Tiny hairs, called cilia, line the bronchi and the nose helping to waft unwanted materials up to the mouth in the form of mucus.
Each lung is made up of 'lobe' sections which are like balloons filled with sponge-like tissue. There are three lobes on the right and two on the left, because the left lung shares some space with the heart and is slightly smaller than the right.
Cells in the lungs contain enzymes that are crucial for maintaining the tissues of the lung in a healthy state.