goose bumps

Goose bumps on a person

Goose bumps, also called goose flesh, goose pimples, chill bumps, or the medical term cutis anserina, are the bumps on a person's skin at the base of body hairs which may involuntarily develop when a person is cold or experiences strong emotions such as fear or awe. The reflex of producing goose bumps is known as horripilation, piloerection, or the pilomotor reflex. It occurs not only in humans but also in many other mammals; a prominent example are porcupines which raise their quills when threatened, or sea otters when they encounter sharks or other predators.

Etymology

The "goose bumps" (also "goosebumps" or "chicken skin") effect gets its name from geese. Goose feathers grow from stores in the epidermis which resemble human follicles. When a goose's feathers are plucked, its skin has protrusions where the feathers were, and it is these bumps which the human phenomenon resemble. It is not clear why in English the particular fowl goose was chosen, as most other birds have this same anatomical feature. The term "goose bumps" is misleading because the bumps on a goose's skin does not qualify as piloerection, though birds do have the same reflex of extending their feathers out, a function of keeping themselves warm.

The German word is a mimic^{[citation needed]} of English, referring to it as Gänsehaut, i.e. "goose skin", as it is in Italian (la pelle d'oca) and Russian (гусиная кожа). In other languages, however, the "goose" may be replaced by other kinds of poultry. For instance, "hen" is used in Spanish (la piel de gallina) and Romanian (piele de găină), "Chicken" is used in French (la chair de poule), Dutch (kippenvel), Korean (닭살), Chinese (雞皮疙瘩) and Afrikaans (hoendervleis). In Hindi it is called "rongtey khade ho jaana".The equivalent Japanese term, 鳥肌, torihada, translates literally as "bird skin".

The same effect is manifested in the root word "horror" in English, which is derived from Latin horrere, which means "to bristle", and "be horrified", because of the accompanying hair reaction.

Anatomy and biology

Goose bumps are created when tiny muscles at the base of each hair, known as arrectores pilorum, contract and pull the hair erect. The reflex is started by the sympathetic nervous system, which is responsible for many fight-or-flight responses.

As a response to cold: in animals covered with fur or hair, the erect hairs trap air to create a layer of insulation. Goose bumps can also be a response to anger or fear: the erect hairs make the animal appear larger, in order to intimidate enemies. This can be observed in the intimidation displays of chimpanzees,^[1] in stressed mice^[2] and rats, and in frightened cats. In humans, it can even extend to piloerection as a reaction to hearing nails scratch on a chalkboard, listening to awe-inspiring music,^[3] or feeling or remembering strong and positive emotions (e.g., after winning a sports event).^[4]

Piloerection as a response to cold or emotion is vestigial in humans; as humans retain only very little body hair, the reflex (in humans) now provides no known benefit.

In humans, goose bumps are strongest on the forearms, but also occur on the legs, neck, and other areas of the skin that have hair. In some people, they even occur in the face or on the head. In humans, the areolas of the breasts of females typically show piloerection because of hormonal distribution, for example, when aroused or inside the maternity cycle.

Piloerection is also a (rare) symptom of some diseases, such as temporal lobe epilepsy, some brain tumors, and autonomic hyperreflexia. Goose bumps can also be caused by withdrawal from opiates such as heroin. A skin condition that mimics goose bumps in appearance is keratosis pilaris.

Hypothetical explanation

As with birds fluffing their feathers, the hair follicles contract causing the hair (feather) to stand on end. The contraction relaxes and the hairs (feathers) fall into place and align with one another, forming a better insulated coat (and aerodynamics for birds). On thicker furred animals, this realignment of the coat may provide protection during fights and/or hunts which could explain why humans experience this upon being frightened. This would be especially important in haired marine mammals to trap air between the hairs.^{[citation needed]}

References

1. ^ Martin Muller and John Mitan. Conflict and Cooperation in Wild Chimpanzees. Advances in the Study of Behavior, vol. 35
2. ^ Masuda et al. Developmental and pharmacological features of mouse emotional piloerection. Experimental Animals, 1999 Jul;48(3):209-11. PMID 10480027
3. ^ David Huron. Biological Templates for Musical Experience: From Fear to Pleasure. Abstract
4. ^ George A. Bubenik. Why do humans get "goosebumps" when they are cold, or under other circumstances? [1]

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