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 hiatuses and ran to July 2010 and Book 2 was pushed to late 2013. Ultimately, after further delays on Book 2, Smith decided to turn the second half of "Batman: Widening Gyre" into a separately titled mini-series called "Batman: Bellicosity". Following a tip from Nightwing, Batman discovers Arkham Asylum is completely overgrown with plant life. Upon investigation, Batman finds that Poison Ivy is currently in a dispute with Etrigan the Demon, and she has been turning Arkham Asylum into a fortress to protect herself. Batman and Etrigan do battle, but Batman is on the losing end. As Etrigan is about