With temperatures dropping and winter well on its way, most of us have developed little goose bumps and shivers. So why does our body react this way to the cold? Shivering is a way for our bodies to make the muscles contract and relax in very quick succession, causing the entire body to quiver. It is a response that warm-blooded animals have to hypothermia. When the core body temperature drops, a signal is sent to the brain (hypothalamus) which stimulates the muscle contractions or the shivers. The contracting and relaxing of the muscles produces heat, allowing the body to warm up. Muscle movement results in some kind of motion and the heat is wasted energy, but in the case of shivering the heat produced is maintained for warmth. In fact infants and young kids have to be kept warm since they experience more heat loss than adults due to their inability to shiver to maintain body heat.
Goose bumps or cutis anserina is another curious symptom of the cold. Cold temperatures, emotional stimuli or skin irritation trigger involuntary muscle contractions raising the hairs of your skin to produce goose bumps. This cold res-ponse is called piloerection helping keep the air near the skin still as a result retaining heat for the body. Animals that have fur or hair do this as well providing their bodies with insulation. Goose bumps arise when the muscle, arrectores pilorum, at the base of each hair contracts and pulls the hair erect. Goose bumps are also produced as a response to anger or fear, the erect hair makes animals look more intimidating by allowing them to appear larger. Have you seen a frightened cat? This phenomenon occurs in many other animals too. But humans aren’t very good at this given how little hair we have therefore it has become vestigial. But here is an interesting fact. The Latin word “horrere”, the root word for “horror” means “to bristle” or “stand on end” suggestive of the accompanying hair reaction to a horror film.
The writer is a Ph.D. in Molecular Genetics and Genomics and is working on skin cancer at Novartis