Adipose tissue exist in two different forms which can be distinguished with the free eye by their color: white adipose tissue and brown adipose tissue. Both have a highly differing fine structure. Furthermore, their location differs significantly. White adipose tissue is found in the subcutaneous tissue where it exists mainly as single adipocytes or in the peritoneal cavity where it forms a compact tissue. The adipocytes of the white adipose tissue contain a single lipid droplet and therefore are referred to as univacuolar (or unilocular) adipocytes. Since the size of the lipid droplet can vary considerably, white adipocytes may measure between 40 and 120μm.