What Causes Goosebumps
What Causes Goosebumps? Goosebumps are due to an autonomic response of your sympathetic nervous system. It is an involuntary response to stimuli that causes little bumps to appear on your skin. They may occur due to fear, chill, excitement, or emotional stress and are considered harmless. When the sympathetic nervous system is activated, it may cause the arrector pili muscles, also known as hair erector muscles, to contract, raising the hair. Each arrector pili muscle is a bundle of smooth muscle fibers that connect to a follicular unit (several follicles) and is often involved in a self-defence response in mammals. Have you ever witnessed a cat’s fur standing on end when angry or frightened? In effect, this is cat goosebumps, an effect that helps them look larger to fend off predators.