cholesterol is also called cholesterol. a derivative of cyclopentane polyhydrophenanthrene. as early as the 18th century, people had discovered cholesterol from gallstones. in 1816, the chemist benshall named this lipid-like substance cholesterol. cholesterol is widely present in animals, especially in the brain and nervous tissue. cholesterol is also found in kidneys, spleen, skin, liver and bile. its solubility is similar to fat, insoluble in water, and easily soluble in solvents such as ether and chloroform. cholesterol is an indispensable and important substance for animal tissue cells. it not only participates in the formation of cell membranes, but also is the raw material for the synthesis of bile acids, vitamin d and steroid hormones.