Epithelial Cell Questions

[sglass]

For Biology we are supposed to interview an expert on the subject of cells. No expert answered me so I decided to post my questions on here. Feel free to answer them it would be greatly appreciated.

1.) What exactly are epithelial cells?
2.) Are there different types of epithelial cells?
3.) What are epithelial cells being used for?
4.) Could these cells be used to help people with medical problems such as disease or paralysis?
5.) Are these cells causing any controversy in the same degree as stem cells?
6.) Could we live without these cells?
7.) What is the purpose of the mucus secreted by some epithelial cells?
8.) Does the structure of these cells change depending on what they are covering or protecting?

[kolean]

Google it. Wiki's:

http://en.wikipedia.org/wiki/Epithelium