Final answer:
The direct pupillary reflex assesses the integrity of both the optic nerve (CN II) as the afferent limb and the oculomotor nerve (CN III) as the efferent limb. It is a response where pupils constrict when light is shone into the eye, involving sensory input and a motor response.
Step-by-step explanation:
The direct pupillary reflex assesses the integrity of two different cranial nerves: the optic nerve (CN II) and the oculomotor nerve (CN III). When light is shone into the eye, the pupillary light reflex begins with the sensory input traveling through the optic nerve, which constitutes the afferent branch of the reflex. This signal is then relayed to the oculomotor nerve - specifically the Edinger-Westphal nucleus, which is part of the oculomotor complex. The efferent response travels from there through the oculomotor nerve to the ciliary ganglion in the eye, where postganglionic fibers stimulate the circular fibers of the iris to contract and constrict the pupil. Therefore, Option 1 and Option 2 are both involved in the direct pupillary reflex, with the optic nerve as the afferent limb and the oculomotor nerve as the efferent limb.