Did you know you have a goosebumps muscle? We get goosebumps when tiny muscles in our skin’s hair follicles called arrector pili pull our hair upright. Goosebumps evolved when humans had enough body hair for this “hair-raising” action to keep them warm. We still get goosebumps, but they no longer serve a purpose in humans.
How do the goosebumps muscles work?
The arrector pili muscle is a small muscle located at the base of each hair follicle. When this muscle contracts, it causes the hair follicle to stand upright, resulting in the characteristic “goosebumps” or “gooseflesh” that many people experience in response to cold temperatures, emotional arousal, or certain stimuli.
The contraction of the arrector pili muscle can also cause the hair follicle to become more sensitive to the surrounding environment, which may help to protect the skin from cold temperatures or other environmental factors. This contraction is also mediated by the sympathetic nervous system, which is activated in response to certain stimuli such as cold, fear, anger, or pleasure.
Why do we get goosebumps?
Goosebumps occur as a response to a variety of stimuli. The most common trigger is a change in temperature, such as feeling cold. Goosebumps also occur in response to emotional stimuli such as fear, awe, or pleasure. This is because the contraction of the arrector pili muscle is mediated by the sympathetic nervous system. That is activated in response to these stimuli.
Another reason why we get goosebumps is an evolutionary one. When our ancestors had more hair on their bodies, the contraction of arrector pili muscles would make the hair stand up. This created a thicker layer of insulation to help them stay warm in cold temperatures. This response is still present in humans, even though most of us have less body hair.
Goosebumps can also occur when listening to music. This is because the emotional response to music can activate the sympathetic nervous system, which triggers the contraction of the arrector pili muscle.
Overall, goosebumps are a physiological response to a variety of stimuli that can be triggered by both environmental and emotional factors. — WTF fun facts
Source: “What Goosebumps Are For” — National Institutes of Health