Severe injury to skeletal muscle can be significant enough to raise CK-MB levels above normal, but such injury doesnât usually cause a high relative index. If your doctor suspects injury to both heart muscle and skeletal muscle, troponin is a more accurate test for identifying a heart attack.
The radial smooth muscle layer (dilator pupillae) is responsible for dilating the pupil. Source(s): http://en.wikipedia.org/wiki/Iris_%28ana...http://en.wikipedia.org/wiki/Dilator_pup...LaughingMan Â· 8 years ago.he iris is composed of two smooth muscle layers, arranged radially and circularly.
The physiology behind a normal pupillary constriction is a balance between the sympathetic and parasympathetic nervous systems. Parasympathetic innervation leads to pupillary constriction. A circular muscle called thesphincter pupillae accomplishes this task. The fibers of the sphincter pupillae encompass the pupil. The pathway of pupillary constriction begins at the Edinger-Westphal nucleus near the occulomotor nerve nucleus.