Adipose tissue. Coloured Scanning Electron Micro- graph (SEM) of the large fat cells that make up adipose connective tissue. The round cells (green) are known as adipocytes. They are supported by connective tissue fibres (pink). Adipocytes are one of the largest cell types in the human body, each cell being 100 to 120 microns in diameter. Almost the entire volume of each adipocyte is occupied by a single lipid droplet. Adipose connective tissue forms a thick layer under the skin. It functions as an insulating layer and energy store. Magnification: x360 at 6x4.5cm size. Magnification; x380 at 6x7cm size.