Carbohydrate metabolism

Carbohydrate metabolism is a complex of processes of transformation of carbohydrates in the body of humans and animals.
The process of transformation of carbohydrates (see) begins with their digestion in the mouth, where there is a partial breakdown of starch under the action of the enzyme saliva - amylase. Mostly carbohydrates are digested and absorbed in the small intestine, where polysaccharides (see) with the help of enzymes broken down to monosaccharides (see) and then through the blood posted in tissues and organs, and the main part of them, mainly glucose accumulates in the liver as glycogen. Glucose from the blood arrives in those organs or tissues, where there is need for it, and the velocity of penetration of glucose into cells is determined by the permeability of cell membranes. In liver cells glucose enters freely into muscle cells entry of glucose is associated with energy consumption; during muscular work permeability of cell walls increases significantly. If necessary, the glycogen in the process of glycogenolysis becomes phosphorylated form of glucose (phosphate ester glucose). In cells glucose can undergo transformation as anaerobic (glycolysis)and aerobic (pentony cycle). In the process of glycolysis on each molecule split glucose formed 2 molecules of adenosine triphosphate (ATP) and 2 molecules of lactic acid. If tissue sufficiently supplied with oxygen, pyruvic acid (the intermediate product of carbohydrate metabolism, formed in the process of anaerobic decomposition of carbohydrates) is not restored to the breast and is oxidized in the tricarboxylic acid cycle (see Oxidation of biological) to CO2 and H2O with the accumulation of energy in the form of ATP in the system of oxidative phosphorylation (see).
The oxidation of glucose in pentose cycle is formed restored nicotinamide-actinolite-phosphate required for recovery syntheses. In addition, intermediate products pantotenova cycle are material for the synthesis of many important connections.
Regulation of carbohydrate metabolism is largely carried out by hormones and Central nervous system. Corticosteroids (cortisone, hydrocortisone) slow down the speed of transport of glucose into the cells of tissues to insulin (see) quickens him; adrenaline (see) stimulates the process of sharovnya of glycogen in the liver. The bark of the big hemispheres also owns a certain role in the regulation of carbohydrate metabolism, as factors psychogenic character enhance the education of sugar in the liver and cause hyperglycemia. On the status of carbohydrate metabolism can be judged by the content of sugar in blood (norm 70-120 mg%). Diabetes load this value increases, but then quickly reach the standards. Disorders of carbohydrate metabolism occur in various diseases. So, with a lack of insulin comes diabetes. Reduction of activity of one of the enzymes of carbohydrate metabolism and muscle phosphorylase - leads to muscular dystrophy. Cm. also the Metabolism and energy.