Lung

Lung tissue fills most of the chest behind the ribs. When we inhale, air travels through the nose or mouth, down the trachea, and into branching tubes called bronchi and bronchioles. These tubes end in millions of tiny bubbles named alveoli where gas exchange happens.

The muscle that powers breathing is the diaphragm. It flattens when we breathe in, giving the lungs space to expand, and springs back when we breathe out. Ribs and intercostal muscles assist by lifting the chest like bucket handles, making room for air.

Alveoli walls are only one cell thick and sit beside capillaries. oxygen slips into the blood, while carbon dioxide, a waste gas, slips out to be exhaled. Mucus and tiny hairs called cilia line the airways, catching dust and germs before they reach these delicate sacs.

Lungs are happier with clean air, plenty of water, and regular movement. Running, singing, or laughing deeply exercises the diaphragm and keeps the air sacs stretchy. Vaccines, hand washing, and avoiding tobacco or smoky fires protect lungs from infections and long-term damage.

Doctors listen to lung sounds with a stethoscope and measure airflow with a spirometer if someone has asthma or another breathing problem. When lungs are injured or sick, technology such as inhalers, oxygen therapy, or even extracorporeal membrane oxygenation (ECMO) can lend a hand until they heal.