What Causes Goose Pimples?
Sometimes when we are cold or frightened, little bumps, called goose pimples, form on our skin. We may also get a prickly feeling that makes us think our hair is standing on end. Goose pimples are caused by tiny muscles at the hair roots in the skin.
When the skin is suddenly chilled, the tiny muscles tighten up. They form little bumps on the skin and make the hairs stand up straighter than usual. This is the body’s way of preserving its own heat by causing the hairs on the skin to stand up, thus reducing heat loss. Goose pimples are often seen in conjunction with shivering in these instances.
The reflex of producing goose pimples is known as arasing, piloerection, or the pilomotor reflex. It occurs in many mammals besides humans; a prominent example is porcupines, which raise their quills when threatened. Cats and dogs also have little hair-erector muscles in their skin. When the animal is startled or angry, the muscles make the hair stand up.
The formation of goose pimples or bumps in humans under stress is considered by some to be a vestigial reflex, some believe its function in human ancestors was to raise the body’s hair, making the ancestor appear larger and scaring off predators.
People often say they feel their “hair standing on end” when they are frightened or in awe. In an extremely stressful situation, the body can employ the “fight or flight” response. As the body prepares itself for either fighting or running, the sympathetic nervous system floods the blood with adrenaline (epinephrine), a hormone that speeds up heart rate, metabolism, and body temperature in the presence of extreme stress. Then the sympathetic nervous system also causes the piloerection reflex, which makes the muscles attached to the base of each hair follicle contract and force the hair up.