cross section of a hair strand. section of skin, showing the epidermis and dermis a hair in its follicle the arrector

anatomy hair shaft bulb cross section strand skin epidermis dermis follicle arrector pili muscle sebaceous glands graphic scheme collagen problem layer diagram medulla cortex science realistic structure infographics educational images text vector illustration anatomical detailed medical dermal papilla gland microscopy human keratin scales protein filament crosssection felidae