• Fat (Body)
• Adipose Tissue

Body fat is, in a sense, a body organ. Though this kind of tissue, plump white/yellow knobby layers of fat cells in a net of connective strands, has long been known to store food energy that can power the body when famine strikes - it is only in very modern times that the concept of this amorphous stuff as a functional organ - akin to a spleen or a stomach, has entered human biology.

• The classic teaching about human body fat was that there were two types, like in other animals, brown and white. The brown fat is a high metabolic tissue that was able to generate heat, and burned calories. In some animals, it is abundant and important, but in people, is pretty vestigial - only a bit of it exists along the back between the shoulder blades in new borns; and it son disappears.
• White fat was seen as pretty inert - a cushiony blob of tissue that helps protect organs, like our eyes, but mostly serves as a kind of energy storage source.
• It has become apparent that white fat, otherwise known as adipose tissue or body fat, actually is an endocrine organ which actives makes hormones.