Huxley- Henley layers is a pa of

Hair * Hair is derived from ectoderm, but dermal papilla is of mesoderm-derivation * Hair follicle is positioned at an angle; base of follicle typically within the subcutaneous fat Longitudinal anatomy * Infundibulum: upper poion of follicle extending from surface of epidermis to opening of sebaceous gland * Isthmus: middle poion extending from opening of sebaceous gland duct to inseion of arrector pili muscle (bulge), lined by outer root sheath (ORS), no inner root sheath (IRS) * Inferior segment or lower hair follicle: extending from base of isthmus to hair bulb; consists of matrix cells and envelops dermal papilla; lined by IRS; ORS present but not keratinized; widest diameter termed critical line of Auber (below this is where bulk of mitotic activity occurs); melanocytes in bulb provide melanosomes for hair color * Cross-sectional anatomy:- from outer to inner layer: * Glassy membrane - ORS - Henle's layer (IRS) - Huxley's layer (IRS) - cuticle (IRS) - hair shaft cuticle - coex --> Medulla. Ref:- Sima Jain; pg num:- 13,14