A sphincter muscle that is part of the iris. [ http://en.wikipedia.org/wiki/Iris_sphincter_muscle ]
Synonyms: iris sphincter muscle musculus sphincter pupillae M. sphincter pupillae sphincter muscle of pupil
Term information
- EMAPA:35788
- FMA:49157
- Wikipedia:Iris_sphincter_muscle
- MA:0001289
- UMLS:C0229189 (ncithesaurus:Sphincter_Pupillae_Muscle)
- SCTID:280889004
- BTO:0000656
- NCIT:C33586
uberon_slim
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]
pupillary constrictor muscle
sphincter pupillae
constrictor pupillae
pupillary sphincter
sphincter pupillae muscle
m. sphincter pupillae
pupillary sphincter muscle
circular fibers
iris sphincter
spincter pupillae
iris constrictor
iris constrictor muscle