Through their concentration in cell membranes they may somehow be involved in the transport of hydrophobic constituents into and out of cells. Some blood serum phospholipid may originate in the liver, postprandial serum phospholipid containing dietary fatty acids and glycerol, arises in extrahepatic tissue, probable the intestinal mucosa. The presence of phospholipids in mitochondria is probably not adventitious, by may well play a role in fatty acid oxidation. Lipids are present in all living cells, but the proportion varies from tissue to tissue. The more complex lipids occur closely linked with protein in the membranes of the cell and of subcellular particles.
Human skin is a sensitive and complex organ utilizing miriad cell processes to function.
In today's world, cosmetics are intended not merely to superficially improve the appearance of skin, but to care for, cleanse and maintain the functions of the skin. Phospholipids play an important role in cosmetics because they possess and chemical properties that are needed for the care and maintenance of healthy skin. Phospholipids contain naturally occurring essential polysaturated fatty acids, which can contribute to the activation of cellular metabolism. Phospholipids can bind both water and fat which make them excellent natural co-colubilizers. They can also be used as dissolution agents, dispersant, wetting agents and stabilizers.