The smell nerve
Olfactory nerve (I) · nervus olfactorius
The first cranial nerve, carrying the sense of smell from your nose to your brain.
What it does
Smell receptors high in the roof of the nose send fine nerve fibres up through holes in the ethmoid bone to the olfactory bulbs on the underside of the brain. From there, smell signals go straight to areas involved in memory and emotion, without passing through the thalamus first.
Surprising fact
Smell nerve cells are among the few nerve cells in the body that are regularly replaced throughout life.
Why it matters
That direct route to memory and emotion is why a smell can bring back a childhood memory so vividly. Losing your sense of smell can be an early sign of some illnesses, including viral infections.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.