Mydriasis iris sphincter, composed of circularly arranged muscle fibers, and the iris dilator, composed of radially arranged muscle fibers. The sphincter is innervated by (signaled by nerves of) the parasympathetic nervous system, and the dilator by the sympathetic nervous system. Sympathetic stimulation of the adrenergic receptors causes the contraction of the radial muscle and subsequent dilation of the pupil. Conversely, parasympathetic stimulation causes contraction of the circular muscle and constriction of the pupil. The mechanism of mydriasis depends on the agent being used. It usually involves either a disruption of the parasympathetic nerve supply to the eye (which normally constricts the
The Widening Gyre (album) a fantastic collection of traditional Gaelic songs mixed in with Irish jam regulars. The band is joined by many special guests in this collection of upbeat lively jam tunes as well as slower songs sung by Mairéad Ní Mhaonaigh. [...] This CD is a great mixture of what you would expect from a traditional Irish band combined with American influences." In the May–June 2015 issue of (French magazine) Trad' Mag, folk critic Philippe Cousin awarded "The Widening Gyre" full marks (giving the album a "Bravo!!!" award), stating: "If Donegal is still part of it here, bluegrass colours dot here and