confused...differentiation/dividing cells

[Kiara]

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Hey guys, a random question that I wanted to confirm...

terminally differentiated cells:
rbc's, wbc's, skeletal cells, nerve cells, epithelial skin cells...any others?

Source of confusion was examkrakers q asking which tissues undergo significant cellular division...intestinal mucosa, thymus and epithelial tissues do, and skeletal muscles dont.

Im wondering why if skin epithelial cells are terminally differentiated, they undergo signicant cellular division? Is it b/c they are talking about the diff of the upper layer of skin cells vs. the inner layer??

Any info on this would be much appreciated!

Thanks

 

[RoadRunner17]

I think the term, "terminally differentiated cells" refer to the lack of the cell's ability to differentiate into different cells. For instance skin cells are not pluripotent/totipotent, but are rather unipotent and only divide into identical skin cells... which they happen to do quite frequently due to high turnover. On the other hand, bone marrow is multipotent and can differentiate into RBCs, for instance. They probably do it quite a bit as well since RBCs have a relatively short shelf life, and this doesn't address the BM's ability to differentiate into WBCs and platelets as well. Additionally, most nerve cells are both unipotent and do not divide very often, if at all. There's a difference between the definition of potency (ability to differentiate) and the ability of a cell to divide to replicate itself.

 

[Kiara]

ok cool..thanks 🙂 i think i was trying to match up two unrelated concepts...
just to confirm... skeletal cells...unipotent and dont divide frequently?

in the princeton book they sid "The more specialized a cell becomes, the less likely it is to remain capable of reproducing itself. Examples are neurons, blood cells, and cells on the surface of the skin."

But epithelial cells do divide frequently dont they?

Im probably just over analyzing this...

thanks!