Table 1.

Summary of skin components.^13–17

	Epidermis	Dermis	Subcutis
Thickness (mm)	0.01 to 0.15	1 to 3	1.65 to 18.2
Cell types	Keratinocytes	Fibroblasts	Adipocytes
	Melanocytes	Mast cells	Fibroblasts
	Langerhans	Stem cells
	Merkel cells
Absorbers	Phaeomelanin	Hemoglobin	Hemoglobin
	Eumelanin	Bilirubin	Lipids (fat)
	Water	Water	Water
	Lipid	Beta-carotene
Scatterers	Cells/nuclei/organelles	Collagen	Collagen
			Lipids (fat)
Fluorophores	Keratin, tryptophan, melanin retinol	Tryptophan, tyrosine, flavins, lipofuscin, vitamin A, NADPH, NADP, FAD, collagen, elastin, AGEs, vitamin B, hemoglobin	Collagen, elastin, AGEs, vitamin A, hemoglobin