Why do people get goose bumps?

Goose bumps are a skin condition that people are very familiar with. Goose bumps usually occur under specific conditions. For example, goose bumps will occur when the skin is suddenly stimulated by cold air. This phenomenon is a strategy for the skin to tighten and keep warm. It has no effect on health. There are also many other phenomena that cause goose bumps. Let’s take a look at why people get goose bumps?

Under the sweat hairs on human skin is a small bundle of tissue called arrector pili muscles, which control the movement of sweat hairs. When cold air hits the surface of human skin, the temperature-receiving nerves on the skin surface immediately transmit the message to the brain. The brain issues orders like a commander, shrinking the sweat pores on the skin. Then the arrector pili muscles under the sweat hairs begin to contract, and the sweat hairs stand up one by one. The contracted arrector pili muscles look like small bumps, which can effectively prevent the loss of heat in the body and is a self-defense reaction of the human body to resist cold. This is when you should consider adding some clothing.

Sometimes, when people are frightened, they will get goose bumps on their skin. This is caused by a chain reaction of self-defense nerves.

Small bumps similar to goose skin that appear on the human skin due to fright or cold. This is caused by the contraction of the arrector pili muscles. The arrector pili muscle is a smooth muscle associated with the hair follicles. It is composed of slender bundles of spindle-shaped muscle fibers, one end of which starts from the papillary layer of the dermis and inserts into the connective tissue sheath on the side of the middle part of the hair follicle at the other end, forming an obtuse angle with the skin surface. Therefore, when the arrector pili muscle contracts, the hair stands upright on the skin surface. The spindle-shaped muscle cells become elastin fibers at their starting and terminal ends, which are inserted into the gaps between muscle cells and fixed to form tendon junctions.

When the muscles relax, the hair returns to its original position due to the elastic recovery of the surrounding dermis, and the elastin fibers surrounding the outer hair root sheath are firmly attached to the epidermal cells. In fact, it has less elasticity and greater tension. The activity of the arrector pili muscles is controlled by the adrenergic sympathetic nerves. When mental and emotional changes such as fear and terror occur, the sympathetic nerves are excited, the adrenaline level increases, the arrector pili muscles contract, and the hair stands upright, which is the so-called goose bumps phenomenon.