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 to the Slave Is the Fourth of July? that slavery could be eliminated with the support of the church, and also with the reexamination of what the Bible was actually saying. You profess to believe, "that, of one blood, God made all nations of men to dwell on the face of all the earth," and hath commanded all men everywhere to love one another; yet you notoriously hate (and glory in your hatred) all men whose skins are not colored like your own. Douglass wants his audience to realize that they are not living up to their proclaimed beliefs. He talks about how they, being Americans, are proud