So, you know how your body gets new cells every 20 days?

Question

Does it get all new cells at the same time? Or does every new cell form at a different time? How does it work? Because Im thinking if we get new skin cells all at the same time it wouldnt be possible. However, if it varies with each cell, it would. Can anyone explain this?

Answer 1

Different cells grow and reproduce at different rates, and some cells don't reproduce at all.

Skin cells do reproduce quickly, replenishing your skin regularly. The same is true for blood cells.

Nerve cells, OTOH, reproduce very slowly, if at all.

However, each cell regulates its own internal "clock" of the cell-cycle. Even in your skin, not all cells will be dividing at the same time. In a rapidly-growing tissue like skin, you will find more cells that are dividing, but most cells will still be quiescent (non-dividing).