anatomy of cranial nerve I

Last reviewed 01/2018

The olfactory nerve is purely sensory. The fibres of the olfactory nerve arise in the olfactory epithelium of the roof of the nose on either side of the nasal septum. There are one hundred million receptor neurones here, each with cilia covered in microvilli, onto which inhaled molecules pass.

The other end of the bipolar neurone forms the olfactory nerve fibres which pass in bundles upwards through the cribriform plate of the ethmoid bone to synapse with the dendrites of mitral cells in the olfactory bulb. The axons of the mitral and neighbouring tufted cells make up the olfactory tract along with fibres from the opposite olofactory bulb. This runs under the side of the frontal lobe and terminates in the medial temporal lobe on the same side.