Iris dilator muscle Iris dilator muscle The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle of the eye, running radially in the iris and therefore fit as a dilator. The pupillary dilator consists of a spokelike arrangement of modified contractile cells called myoepithelial cells. These cells are stimulated by the sympathetic nervous system. When stimulated, the cells contract, widening the pupil and allowing for more light to pass through the eye. It is innervated by the sympathetic system, which acts by releasing noradrenaline, which acts on α1-receptors. Thus, when presented with a threatening
There Is a Light That Never Goes Out There Is a Light That Never Goes Out "There Is a Light That Never Goes Out" is a song by the English rock band the Smiths, written by guitarist Johnny Marr and singer Morrissey. Featured on the band's third studio album "The Queen Is Dead", it was not released as a single in the United Kingdom until 1992, five years after their split. It peaked at No. 25 on the UK Singles Chart. The song has received considerable critical acclaim; in 2014, "NME" listed "There Is a Light That Never Goes Out" as the 12th greatest song of all time.