Nerve and muscle tissue don't grow back much but epithelial cells in the skin grow very quickly. Why is that some tissues find it difficult to grow back and are replaced by fibrous scar tissue. Can't they do some mitosis and regrow? Thank you

Well skin cells (and hair cells) grow quickly because they are "disposable". We shed skin and hair cells all the time, and we use it as a continuously growing wall against the outside world. If they weren't rapidly growing, our skin would wear out.

 

Nerves on the other hand, are fairly permanent cells. Even worse, their shape is really really awkward, since cells by default are rounded but nerves have all this long thing branching pattern, and it very much matters that those extensions are in the right place.

 

Also, cells seem to sense the stiffness of surrounding tissue. This may cause problems since nerves prefer soft tissues to grow in but scar tissue is harder.

Well skin cells (and hair cells) grow quickly because they are "disposable". We shed skin and hair cells all the time, and we use it as a continuously growing wall against the outside world. If they weren't rapidly growing, our skin would wear out.

 

Nerves on the other hand, are fairly permanent cells. Even worse, their shape is really really awkward, since cells by default are rounded but nerves have all this long thing branching pattern, and it very much matters that those extensions are in the right place.

 

Also, cells seem to sense the stiffness of surrounding tissue. This may cause problems since nerves prefer soft tissues to grow in but scar tissue is harder.

 

Thanks once again for the reply Mr Skeptic Yes that makes sense I also like to add something. May be because these cells are so specialized you can't directly reproduce them. Like a person with a lot of experience you can't just clone him but get experience from starting from square one. Stem cells can be used to start from square one.

There should be different proteomes in different cell types, and it is these proteins sensing environment through signal transduction and also which intrinsically determine the potential for regeneration.