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
Kinnikuman Muscle Grand Prix complete the mode and to watch the ending credits. The "Challenge" class is a 4-fighter series where the player has to beat 2 of them to be classified as "S" (Gold), "A" (Silver), "B" (Bronze) rank. Being defeated by one of them will result in a game over with a "D" (purple colored medal) rank. The "Muscle" class is an 8-fighter series where the player has to beat 3 of them to be classified as "S" (Gold), "A" (Silver), "B" (Bronze) rank. Being defeated by one of them will result in a game over with a "D" (purple colored medal)