What three systems is the liver involved with?

A large part of amino acid synthesis
The liver performs several roles in carbohydrate metabolism:
Gluconeogenesis (the synthesis of glucose from certain amino acids, lactate or glycerol)
Glycogenolysis (the breakdown of glycogen into glucose)
Glycogenesis (the formation of glycogen from glucose)(muscle tissues can also do this)
The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation
The liver also performs several roles in lipid metabolism:
Cholesterol synthesis
Lipogenesis, the production of triglycerides (fats).
The liver produces coagulation factors I (fibrinogen), II (prothrombin), V, VII, IX, X and XI, as well as protein C, protein S and antithrombin.
In the first trimester fetus, the liver is the main site of red blood cell production. By the 32nd week of gestation, the bone marrow has almost completely taken over that task.
The liver produces and excretes bile (a yellowish liquid) required for emulsifying fats. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
The liver also produces insulin-like growth factor 1 (IGF-1), a polypeptide protein hormone that plays an important role in childhood growth and continues to have anabolic effects in adults.
The liver is a major site of thrombopoietin production. Thrombopoietin is a glycoprotein hormone that regulates the production of platelets by the bone marrow.