The trachea (TRAY-kee-uh) is the tube that carries air from your nose and mouth down into your lungs. You can feel it in the front of your neck, where it sits just behind your skin. Sometimes people call it the windpipe because that's exactly what it does: it pipes air into and out of your body with every breath.

Your trachea is about four inches long and made of tough rings of cartilage (the same flexible material that shapes your ears and nose). These rings keep the tube open all the time, like a vacuum cleaner hose that doesn't collapse. Without those rings, your trachea might squeeze shut when you bend your neck or turn your head.

At the top, your trachea connects to your larynx (the voice box), and at the bottom it splits into two branches called bronchi, with one going to each lung. A small flap called the epiglottis covers your trachea when you swallow, keeping food and water from going down the wrong pipe. When something does slip past that flap, you cough violently to protect your trachea and lungs, which explains why choking on water can feel so alarming.