How can some cells in the human body, such as skin cells, continue to divide...?

How cansome cells in the human body, such as skin cells, to continue to divide, while others, such as nerve cells, stop dividing after they reach maturity?

How can some cells in the human body, such as skin cells, continue to divide...?
It's to do with their function.





Skin cells are constantly being exposed to toxic, damaging conditions. So they are constantly being sloughed off our skin after dying, and will require constant replacement. The same is true of the cells lining our intestines.





Other cells - such as the uterus lining - are similarly being lost in large numbers as part of their function. Red blood cells are specialised to carry oxygen, and have lost their nucleus - so they cannot divide. But they are constantly being replaced from populations of hematopoetic stem cells in your bone marrow, which undergo constant division.





Nerve cells, OTOH, are not normally exposed to such harsh conditions, and - in order to function - they *must* maintain their interconnections, so cannot just die off without consequence (even if they were replaced). Therefore they are not specialised to divide.





Most cell types in the body are sort of "halfway" between these two extremes: the cells don't normally divide, but they can be induced to do so by certain conditions. Muscle cells, for example, do not normally divide, but they will do so if you exercise a lot.
Reply:It's all in the way certain genes are turned on or off.