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
What Do You Say to That What Do You Say to That "What Do You Say to That" is a song written by Jim Lauderdale and Melba Montgomery. First recorded by David Ball on his album "Play", it was later recorded by George Strait on his album "Always Never the Same". Strait's version was released in July 1999 as the third and final single from this album. It peaked at number 4 in the United States, and number 2 in Canada. Larry Flick, of "Billboard" magazine reviewed the song favorably, calling it a "lovely little tune with a pretty melody and a positive lyric." He goes