United States or Djibouti ? Vote for the TOP Country of the Week !
In this chest-cage are millions of tiny air bags that make up the lungs; and every time you take a breath, the air bags are puffed out with the fresh air that comes rushing in. By the time you let your ribs sink again, the air has given its oxygen to the blood, and the blood has poured its carbon-dioxid smoke into the air bags for you to breathe out.
By lifting your ribs, you have made the chest-cage larger; and the air has rushed into your nose, down your windpipe, and filled your lungs. If you breathe very deeply, you will find that your stomach, too, swells out. This shows that the muscular bottom of the cage, called the diaphragm, has been pulled down, making the cage larger still.
Perhaps your teacher can show you the skeleton of some animal. You will notice how the rings, or ribs, slant and are joined by hinges behind to the backbone and in front to the breastbone. It looks somewhat like a cage, doesn't it? Put your hands on the sides of your chest and you can feel your own ribs. Do they slant upward or downward? This chest-cage is our breathing-machine.
Word Of The Day