the creation of mechanical protection around the organs in the form of fat pads
endocrine function, then there is a selection in the blood of many substances.
Adipose tissue is of two kinds: White brown.
White adipose tissue performs all four functions, but the brown adipose tissue plays a very special role. In humans, white adipose tissue in humans is much more than brown. White adipose tissue is white or yellowish in color, whereas brown adipose tissue is actually brown, brownish color. The color brown fat is due to a large number of iron-containing pigment - cytochrome.
The function of brown adipose tissue - heat, it warms the body. That's why a lot of animals that hibernate in winter. When an animal sleeps in winter, it does not move, and heat through muscle contraction is almost off. The temperature of their body is supported by the brown adipose tissue. In the adult human brown adipose tissue is very little. In infants it is much more, but with the growth of its decline. In humans, brown adipose tissue in its pure form, there are about kidney and thyroid. In addition, between the shoulder blades to the chest and shoulders in a mixed human adipose tissue, consisting of both white and brown adipose tissue. As they get older the amount of brown adipose tissue is reduced
Fat cell called the "adipocyte". This name is from the Latin element "adeps", which means "fat" and the Greek element "kytos", which means "hollow bubble." Fat cells in their study under the scanning electron microscope, have the form of balls, surrounded by collagen fibers and blood capillaries.
Cells were white and brown adipose tissue are significantly different from each other. White adipose tissue cell has within himself a big fat bubble. This lipid vesicle occupies almost the entire cell, pushing to the periphery of the cell nucleus, which becomes flattened. Brown fat cell has a lot of small bubbles of fat, so its kernel is rounded. In addition, the brown fat cell a lot of mitochondria, which are, in fact, give it a brownish color. It is found in mitochondria cytochrome pigment, and it occurs in the mitochondria of the biochemical processes that lead to the heat. Heat is produced with the participation of a unique protein, called termogenin.
65-85% by weight of adipocytes (fat cells) is fat. This fat is in the form of triglycerides (triacylglycerols), ie compounds consisting of glycerol and three fatty acid molecules (for details about the structure of triglycerides and their functions can be found here). The main function of triglycerides in the body - a source of energy for their decomposition.
People with more weight in fat accumulated dozens of kilograms of triglycerides, which have enough energy to support metabolic rate for several months. Compared with other substances (carbohydrates, proteins) for energy storage fats have a number of advantages - they can accumulate in large amounts in pure form, and per unit of weight they contain twice as much energy as carbohydrates. For the record: 1 kilo of fat a person has the energy of about 8750 kcal.
"Some animals triacylglycerols reserves under the skin perform two functions: they serve as an energy depot and form insulating layer, which protects the body from the effect of very low temperatures. Seals, walruses, penguins and other warm-blooded animals in the Arctic and Antarctic regions are provided with powerful layers of triacylglycerols Mechanical protection
Adipose tissue not only provides mechanical protection around the organs, but also creates a bed for them. For example, the "fat pad" kidney holding it in place. It is known that the omission of the kidney is only found in very thin people.
The endocrine function
Recently received a lot of interesting data that adipose tissue cells is not simply a repository of stored energy, and is an active endocrine organ that is the body produce hormones. The most studied in the present allocation of the fat cells of two hormones - estrogen and leptin.
Leptin was first isolated in 1994. He drew worldwide attention as a potential cure for obesity. Initially it was assumed that when a person eats, fat cells release leptin, it enters the brain and causes a feeling of satiety. However, it was not quite so simple. Introduction of leptin during a meal did not cause satiety. It turned out, the level of leptin in the blood regulates the duration of the interval between meals. The lower levels of leptin, the more often a person eats. Further studies showed that the use of leptin as a drug for weight loss does not make sense, since its level in the blood of obese people, and so elevated.
Estrogens. Adipose tissue has aromataznoy activity. It contains the enzyme aromatase P450, which converts testosterone, that is the male sex hormone in the female sex hormone, estrogen. The conversion speed increases with age, as well as increased fat accumulation. Fat cells are captured testosterone from the blood and excrete it into estrogen. Special aromataznoy activity differs fat accumulated in the abdomen. Thus, it becomes clear, where does the little woman's breasts in men with a big "beer" belly, why they have reduced potency and fertility