arrector pili

anatomy

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Last updated

June 18, 2026

Quick Summary

The arrector pili are small muscles attached to hair follicles. When these muscles contract, they cause the hair to become erect and the follicle to be pulled upward. This action creates a bump on the skin's surface, commonly known as gooseflesh or goosebumps. This response is an involuntary reflex, often triggered by cold, shock, or fright, and is part of the sympathetic nervous system's reaction. The contraction of arrector pili muscles is also referred to as piloerection.12

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integument
Hair
A small muscle, the arrector pili, is attached to each hair follicle, with the exception of the small follicles that produce only fine vellus hairs. If this muscle contracts, the hair becomes more erect and the follicle is dragged upward. This creates a protuberance on the skin surface, producing…
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A small muscle, the arrector pili, is attached to each hair follicle, with the exception of the small follicles that produce only fine vellus hairs. If this muscle contracts, the hair becomes more erect and the follicle is dragged upward. This creates a protuberance on the skin surface, producing…
Read More