<P> It is controlled by parasympathetic fibers of the muscarinic acetylcholine receptor ( M3 ) that originate from the Edinger - Westphal nucleus , travel along the oculomotor nerve ( CN III ) , synapse in the ciliary ganglion , and then enter the eye via the short ciliary nerves. . The short ciliary nerves then run forward and pierce the sclera at the back of the eye , traveling between the sclera and the choroid to innervate the iris sphincter muscle . </P>
<P> It is controlled by parasympathetic fibers of the muscarinic acetylcholine receptor ( M3 ) that originate from the Edinger - Westphal nucleus , travel along the oculomotor nerve ( CN III ) , synapse in the ciliary ganglion , and then enter the eye via the short ciliary nerves. . The short ciliary nerves then run forward and pierce the sclera at the back of the eye , traveling between the sclera and the choroid to innervate the iris sphincter muscle . </P>
the circular muscle of the iris uses which parasympathetic receptor
the circular muscle of the iris uses which parasympathetic receptor
the muscarinic acetylcholine receptor ( M3 )
the muscarinic acetylcholine receptor ( M3 )