🔬 A hair follicle is a complex miniature organ embedded in the dermis of mammalian skin, consisting of multiple specialized cellular components arranged in concentric layers. The innermost layer comprises the hair shaft, surrounded by the inner root sheath (IRS), which is composed of three distinct layers: Henle's layer, Huxley's layer, and the IRS cuticle. The outer root sheath (ORS) envelops these structures and contains stem cells in the bulge region, crucial for follicular regeneration and wound healing.⁠ ⁠ At the base of the follicle lies the hair bulb, which houses the dermal papilla—a mesenchymal component that regulates hair growth through various signaling molecules. The matrix cells surrounding the dermal papilla are highly proliferative and give rise to the hair shaft and IRS through a process of terminal differentiation. The follicle is also associated with a sebaceous gland, arrector pili muscle, and a rich network of nerve endings and blood vessels that support its metab...