Iris dilator muscle Iris dilator muscle The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle of the eye, running radially in the iris and therefore fit as a dilator. The pupillary dilator consists of a spokelike arrangement of modified contractile cells called myoepithelial cells. These cells are stimulated by the sympathetic nervous system. When stimulated, the cells contract, widening the pupil and allowing for more light to pass through the eye. It is innervated by the sympathetic system, which acts by releasing noradrenaline, which acts on α1-receptors. Thus, when presented with a threatening
Muscle car Chrysler 300 is also recognized as one of the best-handling cars of its era. Studebaker entered the muscle car scene in 1956 with the Golden Hawk powered by a Packard V8 with . For the 1957 model year, the Rambler Rebel was the fastest stock American sedan according to "Motor Trend". "Musclecar Enthusiast" magazine describes this was "what some people believe to be the very first muscle car." the compact-sized (for the era) unibody 1957 Rebel might be "better known had AMC been successful in their attempt to offer it with Bendix fuel injection." The popularity and performance of muscle