Koreen Bender, age 11, of Carlton, Minn., for her question:
WHAT MAKES US SHIVER AND GET GOOSE BUMPS?
The ways of the human body are wondrous indeed. What's more, most of its miracles go on without our knowledge and often it's mighty hard to understand them. For example, most attacks of shivers and goose bumps occur when the weather is cold. However, they also may occur when we suddenly get scared half out of our wits.
The skin is very, very much alive and in contact with all sorts of other busy organs inside the body. In general, it acts as a smooth, waterproof covering between the inside and the outside. Its sensitive nerves also react to heat, cold and other outside situations and they signal reports to interested organs inside the body.
On a cold day, the skin receptors send signals to the hypothalamus part of the brain, whose business it is to regulate the body's temperature. Orders are issued to relax and contract the muscles below the skin, causing shivering spasms. Muscular exercise of any sort gives off heat. If we just sit around and refuse to exercise in cold weather, the body does the best it can. It orders a shivering spell and this muscular exercise makes us a little warmer.
Goose flesh or goose bumps also occur when the body is too cold for comfort. In this case, tiny muscles near the surface of the skin are ordered to contract. They squeeze up to form little humps and bumps. At the same time, blood is withdrawn from the skin surface, perhaps to prevent warmth from escaping.
Shivering and goose flesh also occur when a patient suffers the ups and downs of a raging fever. First the skin is ordered to release streams of perspiration. As this moisture dries in the air, it takes heat from the skin and the patient cools down.
Then the ups and downs of the fever change and the patient becomes too cool. So the shivering remedy is used to add warmth from muscular exercise. And often at this time the patient gets a bumpy attack of goose flesh.
The hypothalamus brain center acts as a sort of built in thermostat, keeping a constant check on the body's temperature. When things get too warm, it orders perspiration, which cools as it dries on the skin. When things get too cool, it orders shivers and goose bumps to add warmth and conserve the body's heat.
A sudden scare can cause goose bumps and send shivers down the spine. In the world of furry mammals, the goose flesh has an extra use. The little bumps cause the hairs to stand up straight. The frightened animal seems much bigger than he really is and often this scares away his enemy.