Try this link:
http://www.hcvadvocate.org/hepatitis/factsheets_pdf/Fibrosis.pdf
"
Liver fibrosis is not an independent disease but rather a histological change caused by liver inflammation. Liver damage causes liver stellate cells to be over active and triggers the extra cellular matrix (ECM) synthesis to increase. More than normal amounts of collagen fiber deposits in the extra-cellular spaces of the liver cells and causes the liver cells to lose blood infusion and to be hardened."
I got the above from ask.com. You might want to read further there. Basically, I typed in Fibrosis of the Liver, and selected the ask.com choice. It goes on to explain,fairly simply, what fibrosis is etc.
Good luck .