BY SCIENCE BRIDGE ACADEMY
CELLS are constantly regenerated. So is it always new? Or does something in your old body remain? Well, your hair obviously does not stay the same. Each hair is replaced every few years. Fingernails are new every 6 months. The lining of your stomach gets pretty beat up due to constant exposure to acid and bile, so those cells gets replaced every few days. Every few weeks, the outer layer of skin is completely removed. Every few months, you have a fresh army of red blood cells.
A hundred million cells are born every minutes and a hundred million destroyed! You have got a new skeleton every 10 years and new muscles every 15 years. Fat cells however become bigger or smaller when you gain and lose fat mass, they take a very long time to turn over completely. Some cells stick around for your entire life, half your heart for example, as well as neurons which developed before you were born – it is only the connections between them that are constantly changing. Your lens and its core have remained since the moment you first opened your eyes. So how old is your body really? It’s a matter of time, before every part of your body refreshes itself in a similar way. Some of it is brand new; some of it is as old as you!