24/01/2023
The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) divides into two branches, called bronchi, which enter the lungs. The bronchi further divide into smaller and smaller branches (bronchioles), and eventually lead to tiny air sacs called alveoli. The alveoli are surrounded by a network of tiny blood vessels called capillaries. Oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the bloodstream, while carbon dioxide, a waste product of metabolism, diffuses out of the bloodstream and into the alveoli to be exhaled. The diaphragm and intercostal muscles help to expand and contract the lungs during breathing.
