Tiny, smooth muscles attached to hair follicles, contraction causes the hair to stand upright: Term. arrector pili: Definition. This process is vestigial in humans because we don't have enough hair or fur to make it worthwhile. stratum corneum: Definition. Arrector pili muscle Definition A bundle of smooth muscle cells attached to each hair follicle contracts to straighten and raise the hair follicle, resulting in piloerection (goosebumps). Thickend epithelial … brawn; power; force; organ that produces movement Not to be confused with: mussel – a bivalve mollusk or clam Abused, Confused, & … Also know as acne vulgaris' skin disorder characterized by chronic inflammation of the sebaceous glands from retained secretions and Propionibacterium acnes (P.acnes) bacteria. structure with outer and inner root sheaths extending from the epidermal surface into the dermis and from which new hair develops. The integumentary system functions in thermoregulation—the ability of an organism to keep its body temperature within certain boundaries—even when the surrounding temperature is very different. rek′tor pī′lī] Etymology: L, raisers of the hair minute smooth muscles of the skin, attached to the connective tissue sheath of the hair follicles; when they contract they cause the hair to stand erect, producing the appearance called goose flesh. Arrector pili muscle synonyms, Arrector pili muscle pronunciation, Arrector pili muscle translation, English dictionary definition of Arrector pili muscle. When humans become cold, or sometimes scared, we get goosebumps, which are caused by the arrector pili muscle in the skin contracting and pulling the hair shaft upward. Function. It is a specialized form of epidermis that is found over the base of the nails of the fingers. ... arrector pili muscle: Definition. What is one major function of arrector pili muscle contraction that is particularly important in nonhuman mammals? US-Gov / Wikimedia Commons / Public domain. moves hair shaft perpendicular to skin; causes goosebumps: Term. A ribbon of smooth muscle, the arrector pili muscle, extends from the papillary layer of the dermis to the connective tissue sheath surrounding the hair follicle. Structure. The muscle attaches to the follicular stem cell niche in the follicular bulge, splitting at their deep end to encircle the follicle. a) The arrector pili muscle contracts to allow for hair growth b) The arrector pili muscle contracts to shed dead hairs c) The arrector pili muscle contracts to alarm an approaching predator d) All of the above are true Answer: C. Eponychium This type of smooth muscle is observed in the large airways to the lungs, in the large arteries, the arrector pili muscles associated with hair follicles, and the internal eye muscles which regulate light entry and lens shape. D: The arrector pili muscle (APM) consists of a small band of smooth muscle that connects the hair follicle to the connective tissue of the basement membrane. arrector pili: Any of the small muscles attached to hair follicles in mammals; when the muscles contract they cause the hairs to stand on end. When stimulated, the arrector pili muscle pulls on the follicle and raises the hair. 7. hair follicle: Definition. Each is innervated by the sympathetic division of the autonomic nervous system. Definition. Arrector Pili . Layer of epidermis where there is the most rapid cell division: Term. Definition. A tiny, involuntary muscle fiber inserted in the base of the hair follicle is the: arrector pili: The oil glands of the skin connected to the hair follicles are: sebaceous glands: An oily substance secreted from the sebaceous glands is: sebum: The overlapping layer of hair with transparent, scalelike cells is the: cuticle eponychium: Definition. 7. 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