Iris dilator muscle - Wikipedia
The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle [2] of the eye, running radially in the iris and therefore fit as a dilator.
Dilator muscle | Smooth, Ciliary & Sphincter | Britannica
Dilator muscle, any of the muscles that widen a body part. In humans, the dilator muscle of the iris contains fibres that extend radially through the iris of the eye and involuntarily contract as available light decreases, thus dilating the pupil.
Iris Dilator Muscle - an overview | ScienceDirect Topics
The iris dilator muscle is a smooth muscle located in the outer part of the iris that is responsible for dilating the pupil. It is primarily regulated by the sympathetic nervous system through adrenergic receptors, particularly the α1 receptors.
Iris (anatomy) - Wikipedia
The iris (brown coloured portion of the eye) controls the size of the pupil by contracting the sphincter pupillae and dilator pupillae muscles. The sphincter pupillae is the opposing muscle of the dilator pupillae.
How did they find the chemical that makes your pupils dilate?
Feb 25, 2008 · Our pupils naturally dilate in darkness and constrict in bright lights through the actions of two opposing muscles in the iris, the iris dilator and sphincter.
Intraocular muscles - Wikipedia
There are three intrisic ocular muscles: the ciliary muscle, pupillary sphincter muscle (sphincter pupillae) and pupillary dilator muscle (dilator pupillae). [1] [2] All of them are smooth muscles. [2] The ciliary muscle is attached to the zonular fibers and the zonular fibers are the suspensory ligaments of the lens. [2]
Iris dilator muscle - AMBOSS
A smooth muscle that dilates the iris. Innervated by sympathetic fibers from the superior cervical ganglion. These fibers reach the eye by traveling with the long and short ciliary nerves.
Anatomy, Head and Neck: Eye Iris Sphincter Muscle
Jul 30, 2023 · There are two muscles of the iris, and they both consist of smooth muscle. The sphincter muscle contracts the pupil in a circular motion, while the dilator muscles enlarge the pupil by pulling the iris radially.
The Posterior Location of the Dilator Muscle Induces Anterior ...
Mar 9, 2012 · The dilator muscle is a very thin, radially aligned smooth muscle located on the posterior surface of the iris. The dilator extends centrally to the midpoint of the sphincter muscle.
Dilator pupillae - e-Anatomy - IMAIOS
Nerve: Superior cervical ganglion (sympathetics) Action: Pupil dilation. Antagonist: Iris sphincter muscle. The radiating muscular fibers of the iris form the Dilatator pupillae; they converge from the circumference toward the center, and blend with the circular fibers near the margin of the pupil.