Iris sphincter muscle Iris sphincter muscle The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil. It is found in vertebrates and some cephalopods. Initially, all the myocytes are of the smooth muscle type but, later in life, most cells are of the striated muscle type. Its dimensions are about 0.75 mm wide by 0.15 mm thick. In humans, it functions to constrict the pupil in bright light (pupillary light
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