Adipose tissue

White adipose tissue, commonly known as fat tissue, is a type of connective tissue composed of adipocytes. It has several functions, primarily it is the main long term energy storage organ, but it also functions as an endocrine organ, as a mechanical cushion around the eyes and at the tips of the fingers, and for thermal insulation. Brown adipose tissue, a specialized form of adipose tissue which contains many mitochondria, is used to produce heat, and exists mainly in rodents and in hibernating animals

Fat is stored in adipocytes mainly in the form of triglycerides (triacyl glycerol). Glycerol and free fatty acids are taken from the blood, and each three molecules of free fatty acids are conjugated to one molecule of glycerol to form a triacyl glycerol. The tryglycerides are then stored within lipid vesicles within the adipocyte cytoplasm. This form of energy storage is highly efficient, since it does not require the presence of water.