TY - CHAP M1 - Book, Section TI - Hair Findings A1 - Mirmirani, Paradi A1 - Ahdout, Jennifer A2 - Ali, Asra PY - 2015 T2 - McGraw-Hill Education Specialty Board Review Dermatology: A Pictorial Review, 3e AB - Follicles form during third month of gestation; form first on headLining of follicle = ectodermal originDermal papilla = mesodermal originEpidermal invaginations occur at an angle to the surface and over sites of mesenchymal cell collectionsEventually these epidermal cells form a column that surrounds the mesenchymal dermal papilla to form the bulbThe dermal papilla (along with “stem” cells in the bulge) induces hair follicle formation by the overlying epitheliumAdditionally, 2 or 3 other collections of cells form along the follicle:Upper collection becomes the mantle from which the sebaceous gland will developLower swelling becomes the attachment for the arrector pili muscle and where follicle germinal cells reside in telogen phaseIf a third collection of cells exists, it is found opposite and superior to the sebaceous gland and develops into the apocrine gland SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/04/19 UR - dermatology.mhmedical.com/content.aspx?aid=1176103894 ER -