Respiratory System

The respiratory system gives us the breath of life. Air--and the oxygen in it--is as vital as food and its nutrients. With the nose, throat, sinuses, larynx, vocal cords, trachea (windpipe), bronchial tubes, lungs and diaphragm, we have a complex ventilation system that enables us to inhale oxygen molecules and send them to each cell in our body. As we exhale we expel some of the body''''s metabolic trash--carbon dioxide.

* The diaphragm is the main breathing muscle. When you breathe from your diaphragm, you expand your abdominal cavity instead of the chest area, pulling air to the deepest parts of the lungs. Deep breathing is also a major stress-reducing technique. Most of us, though, take inefficient shallow breaths. (To brush up on your breathing, see "Diaphragm Work" on page 206.)

* The bronchial tubes are the two big bronchi that split off from the windpipe (the trachea) and the secondary bronchi that branch out from them. Hyperactive bronchial tubes--too sensitive to pollen, dust, animal dander, cold air or exercise--can provoke asthma attacks. (To handle asthma, see "The Best Defense" on page 208.)

* The airways of each lung look like a sideway tree of many branches. The trunk of the tree is the big bronchus, the larger branches are the secondary and tertiary bronchi and the smaller branches are called bronchioles. Bronchitis is an inflammation of the bronchial airways (the trunk and large branches), usually caused by complications from a viral infection. (To find out how to battle bronchitis, see "Getting the Better of Bronchitis" on page 210.)

* Your voice box--the larynx--sits at the top of your windpipe (the trachea). And your vocal cords--two thin bands--stretch across the top of your voice box. Sometimes overuse or the common cold makes these cords swell--a condition called laryngitis. (When that happens, see the tips under "Tuning Your Instrument" on page 198 for relief.)

The air you breathe comes in through your mouth, goes down your throat and drops into your windpipe. Then it wends its way through the bronchial airways to reach 300 million tiny air sacs called alveoli. Tiny blood vessels called capillaries exchange gases with the alveoli through a thin shared membrane. Oxygen passes from the alveoli to the blood, and outgoing carbon dioxide moves into the lungs where it''''s exhaled.

* The pharynx is just a fancy name for the throat, home of a cold''''s first sign--a sore throat. It''''s the muscular tube that connects the back of the mouth and nose to the esophagus, the tube that leads to the stomach. (For suggestions about how to ease a sore throat, see "Throat" on page 406.)

* The sinuses are eight air-filled cavities around your nose and eyes. Sinusitis occurs when inflammation and infection clog up the cavities'''' normal drains. (To help you breathe easier, see "When It Comes and Stays" on page 354.)