diagram of hair structure anatomy .

hair structure anatomy anagen shaft skin scalp layer root bulb human follicle matrix papilla cross diagram vector flat design infographic epidermis dermis hypodermis anatomical artery vein melanin melanocyte sebaceous glands blood vessles arrector pili muscle physiology cuticle cortex medulla pigment granule keratin biology pigmented head biotin nutrtion dermatology care health dye treatment concept fall loss