Artificial hair integrations is a type of synthetic fiber that can withstand heat up to 400 °F (200 °C), and can actually outlast human hair. It is very similar to human hair given it is tangle-free and has a natural sheen. It can be straightened or curled, however, it takes longer to set and futura cannot be colored. It is sometimes sold as a human hair blend. The human hair shaft is made up of dead, hard protein, called keratin, in three layers. The inner layer is called the medulla and may not be present. The next layer is the cortex and the
Hair cell fish have been found to regenerate, their ability has been studied at length. In addition, lateral line hair cells, which have a mechanotransduction function, have been shown to regrow in organisms, such as the zebrafish. Researchers have identified a mammalian gene that normally acts as a molecular switch to block the regrowth of cochlear hair cells in adults. The Rb1 gene encodes the retinoblastoma protein, which is a tumor suppressor. Rb stops cells from dividing by encouraging their exit from the cell cycle. Not only do hair cells in a culture dish regenerate when the Rb1 gene is deleted, but