Medical questions...?

Question

A young woman is brought into the emergency room with extremely dilated pupils. Her friends stated that she has overdosed on cocaine. What cranial nerve is stimulated by the drug?

Answer 1

substantia niagra.

Next?

Answer 2

Pupillary dilation (called mydriasis) in cocaine overdose is not caused by stimulation of a cranial nerve at all.  In fact, what happens is cocaine inhibits the reuptake of norepinephrine from sympathetic fibers.  So it is acting in the synapse essentially, keeping norepinephrine out there to act on the target (the radial muscle, which is a smooth muscle with adrenergic receptors that respond to NEpi).  Note that this sympathetic pathway is NOT part of a cranial nerve, and the axons are in the superior cervical ganglia, and travel separate from any cranial nerve, into the eye.