10/21 Another sends nerves to the liver, stomach, and other digestive organs, and causes them to do their part in the digestion of the food. Other cells send branches to the muscles and make them act when we wish them to do so. Thus you see how very useful the brain and nerves are. They keep all the different parts of the body working together in harmony, just like a well-trained army, or a great number of workmen building a block of houses. Without the brain and nerves the body would be just like an army without a commander, or a lot of workmen without an overseer. |