Fat cells. Coloured transmission electron micrograph (TEM) of a section through fat (adipose) tissue. Each fat cell, or adipocyte, consists of large central lipid droplets (red) surrounded by a thin layer of cytoplasm (purple), which contains the nucleus. The fat cell is important to the body in maintaining proper energy balance, storing calories in the form of lipids, mobilizing energy sources in response to hormonal stimulation, and commanding changes by signal secretions.Magnification: x2000 when printed at 10 centimetres wide