In biology, adipose tissue /ˈædᵻˌpoʊs/, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. Adipose tissue is derived from preadipocytes and its main role is to store energy in the form of lipids, although it also cushions and insulates the body. Far from being hormonally inert, adipose tissue has, in recent years, been recognized as an endocrine organ, as it produces hormones such as leptin, estrogen, resistin. The two types of tissue are white adipose tissue, which stores energy, and brown adipose tissue. The formation of adipose tissue appears to be controlled in part by the adipose gene, Adipose tissue – more specifically brown adipose tissue – was first identified by the Swiss naturalist Conrad Gessner in 1551. In humans, adipose tissue is located beneath the skin, around internal organs, in bone marrow, intermuscular, Adipose tissue is found in specific locations, which are referred to as adipose depots. Apart from adipocytes, which comprise the highest percentage of cells within adipose tissue, other types are present. SVF includes preadipocytes, fibroblasts, adipose tissue macrophages, and endothelial cells, Adipose tissue contains many small blood vessels. In the integumentary system, which includes the skin, it accumulates in the deepest level, around organs, it provides protective padding. Adipose depots in different parts of the body have different biochemical profiles, under normal conditions, it provides feedback for hunger and diet to the brain. Mice have eight major adipose depots, four of which are within the abdominal cavity, the mesenteric depot forms a glue-like web that supports the intestines and the omental depot and - when massive - extends into the ventral abdomen. Both the mesenteric and omental depots incorporate much lymphoid tissue as lymph nodes and milky spots, the layer of brown adipose tissue in this depot is often covered by a frosting of white adipose tissue, sometimes these two types of fat are hard to distinguish. The inguinal depots enclose the inguinal group of lymph nodes, minor depots include the pericardial, which surrounds the heart, and the paired popliteal depots, between the major muscles behind the knees, each containing one large lymph node. Of all the depots in the mouse, the depots are the largest. In an obese person, excess adipose tissue hanging downward from the abdomen is referred to as a panniculus, a panniculus complicates surgery of the morbidly obese individual. It may remain as an apron of skin if a severely obese person quickly loses large amounts of fat. This condition cannot be corrected through diet and exercise alone, as the panniculus consists of adipocytes and other supporting cell types shrunken to their minimum volume. Reconstructive surgery is one method of treatment, visceral fat or abdominal fat is located inside the abdominal cavity, packed between the organs
The obese mouse on the left has large stores of adipose tissue. It is unable to produce the hormone leptin, resulting in obesity. For comparison, a mouse with a normal amount of adipose tissue is shown on the right.
Morphology of three different classes of adipocytes
Image: Yellow adipose tissue in paraffin section lipids washed out