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brown fat
brown fatn. One of two types of fatty tissue in mammals, especially in newborn infants and hibernating animals, that is composed of dark-colored cells containing numerous mitochondria and lipids, which are converted into body heat.brown fat n (Physiology) tissue composed of a type of fat cell that dissipates as heat most of the energy released when food is oxidized; brown adipose tissue. It is present in hibernating animals and human babies and is thought to be important in adult weight control brown′ fat′
n. brownish yellow adipose tissue that accumulates in hibernating mammals, producing heat if the body becomes too cold. EncyclopediaSeefatbrown fat
fat [fat] 1. the tissue" >adipose tissue of the body.2. a triglyceride" >triglyceride (or triacylglycerol) that is an ester of fatty acids and glycerol. Each fat molecule contains one glycerol residue connected by ester linkages to three fatty acid residues, which may be the same or different. The fatty acids may have no double bonds in the carbon chain (saturated fatty acids), one double bond (monounsaturated), or two or more double bonds (polyunsaturated). Essential fatty acids cannot be synthesized by the body but must be obtained from the diet or from intravenous infusion of lipids.Saturated and Unsaturated Fats. All of the common unsaturated fatty acids are liquid (oils) at room temperature. Through the process of hydrogenation, hydrogen can be incorporated into certain unsaturated fatty acids so that they are converted into solid fats for cooking purposes. Margarine is an example of the hydrogenation of unsaturated fatty acids into a solid substance.brown fat a thermogenic type of adipose tissue containing a dark pigment, and arising during embryonic life in certain specific areas in many mammals, including humans (see illustration); it is prominent in the newborn. Called also brown adipose tissue. Sites of brown fat in the neonate. From McKinney et al., 2000.neutral fat fat (def. 2).polyunsaturated fat a fat containing polyunsaturated fatty acids; see also fat.saturated fat a fat containing saturated fatty acids; see also fat.unsaturated fat a fat containing unsaturated fatty acids; see also fat.brown fatbrown thermogenic tissue composed of cells containing numerous fat droplets and rich in heme-containing cytochromes and mitochondria; lobular masses are found in the interscapular and mediastinal regions, among other locations; although found most commonly in certain hibernating animals, also occurs in pigs, rodents, and human neonates. Synonym(s): brown adipose tissue, hibernating gland, interscapular gland, interscapular hibernoma, multilocular adipose tissue, multilocular fatbrown fatn. One of two types of fatty tissue in mammals, especially in newborn infants and hibernating animals, that is composed of dark-colored cells containing numerous mitochondria and lipids, which are converted into body heat.A special form of fat that generates heat by nonshivering thermogenesis, so designated as it is rich in mitochondria, which imparts a brown hue. Brown fat is rich in sympathetic nerve endings and vessels, its metabolic activity and development is regulated by norepinephrine, and it is normally located in the axillary, subscapular, and interscapular regions, around the large thoracoabdominal vessels, heart, kidneys, and adrenal glands; brown fat is increased in Chagas’ disease, CHF, Duchenne’s muscular dystrophy, malignancy, pheochromocytoma, SIDS, and in malnutritionbrown fat Brown adipose tissue A special form of fat that generates heat by nonshivering thermogenesis, so designated as it is rich in mitochondria, which imparts a pardous hue; BF is rich in sympathetic nerve endings and vessels and its metabolic activity and development is regulated by norepinephrine, and it is normally located in the axillary, subscapular, and interscapular regions, around the large thoracoabdominal vessels, heart, kidneys, and adrenal glands; BF is ↑ in Chagas' disease, CHF, Duchenne's muscular dystrophy, malignancy, pheochromocytoma, SIDS, and in malnutritionbrown fat (brown fat) Adipose tissue located near major vessels that occurs primarily in the full-term newborn, aiding in temperature regulation until shivering is established; it turns white as the infant ages.
Synonym(s): brown adipose tissue, brown adipose, hibernating gland, interscapular gland, interscapular hibernoma, multilocular adipose tissue, multilocular fat. brown fat A kind of animal body fat more readily available for rapid conversion to heat than is normal yellow fat. It is believed that hibernating animals use their brown fat in the recovery from the winter state. Small human babies have deposits of brown fat around the spine.brown fat a special fat layer found between the neck and shoulders of some mammals, e.g. bats and squirrels, whose function is to enable the production of large amounts of heat, particularly after HIBERNATION. The fat is heavily vascularized (see VASCULAR) and has many mitochondria (see MITOCHONDRION), the latter giving it its brown colour due to the presence of mitochondrial cytochrome oxidase. Heat is released by very rapid fat metabolism (rather than the more normal fatty acid metabolism) and is rapidly transported away via the large vascular system. |