However, cirrhosis is defined by its pathological features on microscopy: (1) the presence of regenerating nodules of hepatocytes and (2) the presence of fibrosis , or the deposition of connective tissue between these nodules. The pattern of fibrosis seen can depend on the underlying insult that led to cirrhosis. Fibrosis can also proliferate even if the underlying process that caused it has resolved or ceased. The fibrosis in cirrhosis can lead to destruction of other normal tissues in the liver: including the sinusoids , the space of Disse , and other vascular structures, which leads to altered resistance to blood flow in the liver, and portal hypertension . 
Stages of Liver Damage
A group of enzymes, that are located in the endoplasmic reticulum, known as cytochrome P-450, is the most important family of metabolizing enzymes found in the liver. Cytochrome P-450 is the terminal oxidase component of an electron transport chain. It’s not a single enzyme, but consists of a family of closely related 50 isoforms. Six of them metabolize 90% of drugs. There is a great diversity of individual P-450 gene products and this heterogeneity allows the liver to perform oxidation on a vast array of chemicals, which includes almost all drugs.