In the integumentary system, what is the primary function of the arrector pili muscle associated with hair follicles?

• A. Contracts to elevate the hair, producing goosebumps (piloerection)
• B. Increases cutaneous sweat production by directly stimulating eccrine glands
• C. Secretes sebum into the hair follicle to lubricate hair and skin
• D. Generates the hair shaft by producing keratinized cells in the hair bulb

Answer: (A)

Verified step by step guidance

1. Identify the structure in question: the arrector pili muscle, which is a small smooth muscle attached to hair follicles in the integumentary system.
2. Recall the primary function of the arrector pili muscle, which is to contract in response to stimuli such as cold or emotional states.
3. Understand that when the arrector pili muscle contracts, it pulls the hair follicle upright, causing the hair to stand on end, a phenomenon known as piloerection or 'goosebumps'.
4. Differentiate this function from other options: it does not increase sweat production (that is the role of eccrine glands), secrete sebum (done by sebaceous glands), or generate hair shafts (done by cells in the hair bulb).
5. Conclude that the primary function of the arrector pili muscle is to contract and elevate the hair, producing goosebumps.