http://upload.wikimedia.org/wikipedia/commons/2/2f/Gray878.png

constricts iris

uberon

sphincter pupillae, pupillary constrictor muscle, constrictor pupillae, pupillary sphincter, sphincter pupillae muscle, circular fibers, pupillary sphincter muscle, m. sphincter pupillae, spincter pupillae, iris sphincter, iris constrictor, iris constrictor muscle

UBERON:0001607

WP says: It is found in vertebrates and some cephalopods; this class refers to the vertebrate structure, In humans, it functions to constrict the pupil in bright light or during accommodation. Its dimensions are about 0.75 mm wide by 0.15 mm thick. It is controlled by parasympathetic fibers that originate from the Edinger-Westphal nucleus, travel along the oculomotor nerve (CN III), synapse in the ciliary ganglion, and then enter the eye via the short ciliary nerves. Initially, all the myocytes are of the smooth muscle type, but much later in life, so that ultimately most cells are of the striated muscle type. [WP,unvetted]

• dilatator pupillae

• smooth muscle cell of sphincter of pupil