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
Batman: The Widening Gyre it makes a unique “ka-klack” sound. Wayne hears someone behind him mimic the “ka-klack” sound. A horrified Batman turns around to discover that Baphomet is, in fact, the villain Onomatopoeia. The book ends on a cliffhanger, as Onomatopoeia begins to slit Silver St. Cloud's throat. "Batman: The Widening Gyre" received mixed reviews from critics, as many felt that Smith's trademark brand of crude humor felt out-of-place in a "Batman" comic. Particular criticism was directed at a scene where Batman confesses to Baphomet that, during , he misjudged the power of some explosives he was using, and the resulting blast of