Organ that secretes bile and participates in formation of certain blood proteins. The liver is the largest internal organ, primarily consisting of hepatocytes, and has a wider variety of functions than any other organs in the body. The hepatocyte is a polarized epithelial cell that exhibits both endocrine and exocrine properties. The biliary epithelial cells (cholangiocytes), sinusoidal endothelial cells, hepatic stellate cells (Ito cells), Kupffer cells, and pit cells (liver-specific natural killer cells) represent the majority of non-hepatocyte cell types in the liver. During embryogenesis, the liver is generated in the ventral foregut endoderm.