Ref: Guyton & Hall. Body Temperature Regulation, and Fever. In: Textbook of Medical Physiology. 12th ed. Philadelphia: Saunders Elsevier; 2012. P873. Canong's Review of Medical Physiology, 21st edition.Explanation:'"Brown fat is richly supplied with sympathetic nerves that release norepinephrine, which stimulates tissue expression of mitochondrial uncoupling protein f also called thermogenin). It increases thermogenesis "The lipids in cells are of three main types:Structural lipids - Inherent part of the membranes and other parts of cells; andNeutral fat - Stored in the adipose cells of the fat depots.Brown fatBrown FatMakes up a small percentage of total body fat.More abundant in infants but is present in adults as wellIt is located in:Between the scapulasAt the nape of the neckAlong the great vessels in the thorax and abdomenOther scattered locations in the body* The fat cells as well as the blood vessels have an extensive sympathetic innervation. (Remember. In white fat depots, the principal sympathetic innervation is solely on blood vessels and not on fat cells)Ordinary lipocytes have only a single large droplet of white fat, whereas brown fat cells contain several small droplets of fat.Brown fat contain relatively abundant mitochondria.In these mitochondria, there is the usual inward proton conductance that generates ATP (oxidative phosphorylation) but there is in addition a second proton conductance that does not generate ATP.This "short-circuit" conductance depends on a 32-kDa uncoupling protein (UCP l)It causes uncoupling of metabolism and generation of ATP, so that more heat is producedSympathetic stimulation - Releases norepinephrine - b3-adrcnergic receptors - | lipolysis. - increased fatty acid oxidation in mitochondria - | heat production.Nerve discharge to brown fat is also increased after eating, so that heat production is increased.Hormones secreted by Adipose TissueAdiponectin - Modulates glucose and fat metabolism in liver and skeletal muscleLeptin - Regulated energy homeostasisNorepinephrine (symphathetic stimulation) - Mobilization of free fatty acidsPerilipin - Involed in the formation of lipid droplets in adipocytes.