Which cranial nerve(s) are responsible for the pupillary light reflex (direct/consensual)?Group of answer choicesCN III, IV, VICN IICN II and III

The cranial nerves responsible for the pupillary light reflex (direct/consensual) are CN II and III.

Here's the step by step process:

1. The pupillary light reflex begins when light enters the eye, stimulating photoreceptors in the retina.

2. This sensory information is transmitted by the optic nerve (CN II) to the pretectal nucleus in the brain.

3. The pretectal nucleus sends signals bilaterally to the Edinger-Westphal nucleus.

4. The Edinger-Westphal nucleus then sends parasympathetic fibers via the oculomotor nerve (CN III) to the ciliary ganglion.

5. From the ciliary ganglion, the signal is sent to the sphincter pupillae muscles of the iris, causing them to contract and the pupil to constrict.

So, the optic nerve (CN II) is responsible for carrying the sensory input, and the oculomotor nerve (CN III) is responsible for the motor output of the reflex.