Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, sperm, testicles and retina. It can be synthesized from alpha-linolenic acid or obtained directly from maternal milk or fish oil. DHA's structure is a carboxylic acid (-oic acid) with a 22-carbon chain (docosa- is Greek for 22) and six (hexa-) cis double bonds (-en-); with the first double bond located at the third carbon from the omega end. Its trivial name is cervonic acid, its systematic name is all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid, and its shorthand name is 22:6(n-3) in the nomenclature of fatty acids.