The latest episode of the podcast Invisibilia explores the idea that personality — something a lot of us think of as immutable — can change over time.

That got Invisibilia co-host Lulu Miller wondering if anything about us stays the same. Do all the cells in our body turn over every seven years as is sometimes claimed, with new cells replacing old ones? Or is there something that we hang on to for life?

NPR's Skunk Bear crew decided to answer that question with a video.

It turns out that each body part has its own very distinct lifespan. The lining of the stomach, constantly under assault by digestive acid, is renewed every few days. But bones are refreshed once a decade. And there are a few parts of you that stay with you from birth to death.

SeparatorCopyright 2016 NPR. To see more, visit http://www.npr.org/.