Which term describes the outer surface of the brain that is often called the bark?

• A. Cerebral cortex
• B. Pia mater
• C. Dura mater
• D. White matter

Answer: (A)

The outer surface of the brain is the cerebral cortex. It’s the thin, wrinkled gray matter layer that covers the cerebrum and is where many higher-level functions, like perception, thought, and decision-making, take place. The term cortex comes from the idea of a bark-like covering, which is why it’s sometimes described as the brain’s bark. The other structures are protective coverings and deeper tissue: pia mater and dura mater are meninges that encase the brain, with dura being the tough outer layer and pia the delicate inner layer directly on the brain’s surface; white matter lies beneath the cortex and consists of myelinated axons connecting different brain regions, not the brain’s outer surface.