Hepatic stellate cell in the cell body store vitamin A as retinol ester. The function and role of quiescent hepatic stellate cells is unclear. Recent evidence suggests a role as a liver-resident antigen-presenting cell, presenting lipid antigens to and stimulating proliferation of NKT cells. When the liver is damaged, stellate cells can change into an "activated" state. The activated stellate cell is characterized by proliferation, contractility, and chemotaxis. This state of the stellate cell is the main source of extracellular matrix production in liver injury. This attribute makes it a key factor in the pathophysiology of the liver. The amount of stored vitamin
Proper adjective Proper adjective In English orthography, the term proper adjective is sometimes applied to adjectives that take initial capital letters, and the term common adjective to those that do not. For example, a person from Boston is Bostonian. "Bostonian" is a proper adjective. These terms are used informally only; they are not used by grammarians or linguists. The term "proper noun" denotes a noun that, grammatically speaking, identifies a specific unique entity; for example, "England" is a proper noun, because it is a name for a specific country, whereas "dog" is not a proper noun; it is, rather, a "common noun"