The area between the sebaceous gland and the arrector pili attachment that is filled with follicular stem cells and participates in epidermal regeneration is called what?

The area between the sebaceous gland and the arrector pili attachment that is filled with follicular stem cells and participates in epidermal regeneration is called what?

• A. Hair shaft
• B. Folliculitis
• C. Post inflammatory hyperpigmentation (PIH)
• D. Bulge

Answer: (D)

The bulge is the region that houses follicular stem cells. This niche sits along the outer root sheath between the sebaceous gland and where the arrector pili muscle attaches. Those stem cells are multipotent and can regenerate not only parts of the hair follicle but also the epidermis after injury, which is why this area is described as participating in epidermal regeneration. The other options don’t denote a anatomical region with stem-cell activity: the hair shaft is just the visible hair, folliculitis is an infection of the follicle, and post-inflammatory hyperpigmentation is a pigment change after inflammation.

The bulge is the region that houses follicular stem cells. This niche sits along the outer root sheath between the sebaceous gland and where the arrector pili muscle attaches. Those stem cells are multipotent and can regenerate not only parts of the hair follicle but also the epidermis after injury, which is why this area is described as participating in epidermal regeneration. The other options don’t denote a anatomical region with stem-cell activity: the hair shaft is just the visible hair, folliculitis is an infection of the follicle, and post-inflammatory hyperpigmentation is a pigment change after inflammation.