• Wonderfully Made to Stay Alive
    Awake!—1988 | August 8

    • One example is that of your lungs. First, there is the epiglottis, a small trapdoor that blocks entry to the lungs when you swallow food. Coughing is a second line of lung defense. Third, there is a sticky escalator lining the route to your lungs whereby small invaders are trapped by mucus and removed by the upward movement of tiny bristles.

      The last line of lung defense is scavenger white blood cells. These sanitary agents engulf harmful microscopic particles. Thanks to such mechanisms, our lungs keep working in safety.

      As you read this, your diaphragm is contracting and relaxing. Each contraction sucks air into your lungs, and as the muscles relax, air is pushed out. The diaphragm receives a command to do this about 15 times a minute from a faithful command center in your brain.

      Interestingly, the first book of the Bible, written 3,500 years ago, uses the Hebrew word neʹphesh to describe both man and animals. This word literally means “a breather.”a In a medically accurate manner, the Bible shows that breathing sustains life and that without “the breath of the force of life . . . active in its nostrils,” both man and animals quickly die.​—Genesis 1:20, 21, 24, 30; 2:7; 7:22.

      Other ancient writings contain unfounded speculation about the purpose of breathing. Greek and Roman philosophers, for example, had a strange theory that breathing kept a fire burning within the heart and that this internal flame provided the body with needed warmth.

      This theory remained popular until the 16th century, and it was only in our 20th century that the true purpose of breathing became clear. Oxygen from the air is absorbed by the blood and transported to the trillions of cells that make up the body. Each living cell, in turn, uses oxygen to produce energy. Wherever we go on earth, precious oxygen is available to serve this vital purpose. As an ancient teacher said to a group of Greek philosophers: “The God that made the world and all the things in it . . . gives to all persons life and breath and all things.”​—Acts 17:24, 25.

      Breathing also plays a vital role in keeping the body clean. As the blood passes through the lungs, it unloads carbon dioxide before absorbing a fresh supply of oxygen. When we are active, the level of carbon dioxide in our body rises. A marvelous mechanism prevents the cells from suffocating in this waste. As blood flows through the brain, any rise in the level of carbon dioxide is quickly detected. The command center responds by increasing the rate and depth of breathing.