Final answer:
The afferent limb for the pupillary light reflex is the optic nerve, whereas the efferent limb comprises of the Edinger-Westphal nucleus, oculomotor nerve, ciliary ganglion, and acetylcholine acting on the iris to constrict the pupil.
Step-by-step explanation:
The afferent limb or input pathway for the pupillary light reflex that results in the constriction of the pupil to light is the optic nerve. When light hits the retina, photoreceptors are activated, and the signal travels through the optic nerve to the brain. For the efferent limb or output pathway, the signal is sent from the Edinger-Westphal nucleus through the oculomotor nerve. This efferent signal then travels via the postganglionic fibers from the ciliary ganglion to the iris, where acetylcholine (ACh) is released onto the circular fibers of the iris muscle, leading to constriction of the pupil, reducing the amount of light entering the eye.