Cortex Means Bark, the Outer Layer of a Tree
The cortex is the outer layer of an organ. Anatomists borrowed the Latin word for tree bark.
The cortex is the outer layer of an organ, most familiarly of the brain. Anatomists took the Latin word for tree bark, and the metaphor is precise: the cerebral cortex is a thin sheet, a few millimetres thick, wrapped around the inside of the brain. It is folded so deeply that most of its surface area lies hidden in the grooves.
- The outer layer of an organ. *The cerebral cortex.*
- The outer layer of a plant stem. *The root cortex.*
- Cortical — relating to the cortex. *Cortical activity.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | cortex | The visual cortex. |
| Plural | cortices | Both cortices. |
| Adjective | cortical | Cortical neurons. |
| Opposite | medulla | The adrenal medulla. |
| Related | cork | A cork stopper. |
How it is used in a sentence
- The visual cortex is at the back of the brain.Neuroanatomy.
- The adrenal cortex produces cortisol.Hence the hormone's name.
- Cortex and cork are the same Latin word.Both mean bark.
Cortices in the body
- Cerebral cortex — the folded outer layer of the brain
- Cerebellar cortex — the outer layer of the cerebellum
- Adrenal cortex — produces cortisol and aldosterone
- Renal cortex — the outer part of the kidney
- Medulla — the inner part, in each case
From Latin *cortex*, bark or rind — the same word that gives English *cork*. The hormone *cortisol* is named from the adrenal cortex.
Why is the brain's cortex folded?
Folding packs a large sheet into a small skull. Most of the cortical surface lies inside the grooves rather than on the visible surface.
Are cortex and cork related?
Yes. Both come from Latin *cortex*, meaning bark, which is exactly what cork is.