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
Guided Muscle Guided Muscle Guided Muscle is a 1955 Warner Bros. cartoon in the "Looney Tunes" series featuring Wile E. Coyote and the Road Runner. Along with "The Grey Hounded Hare" and "Tugboat Granny", "Guided Muscle" was one of the three cartoons on the final episode of ABC's "The Bugs Bunny & Tweety Show", on September 2, 2000. In fact, it was the last cartoon seen in that episode. "Introduction": Wile E. Coyote is cooking some food in a tin bucket over a fire. He adds pepper and a drop of a brown liquid, and stirs the bucket and fishes out what