Fat cells. Coloured scanning electron micrograph of fat cells (orange), also known as adipocytes, in human adipose connective tissue. Connective tissue fibres (brown) are seen surrounding and supporting the fat cells. Almost the entire volume of each fat cell is occupied by a single lipid droplet formed largely of triglycerides. Fat not used in metabolic processes in the body is channelled towards these cells through small blood capillaries (not seen). Adipose connective tissue forms a thick layer under the skin. It functions as an insulating layer and energy store. Magnification: unknown.