CARBOHYDRATE METABOLISM
Carbohydrates are broken down into monosaccharides which are absorbed into the blood stream. In the liver and muscles, most of the glucose is changed into glycogen by the process of glycogenesis (anabolism). Glycogen is stored in the liver and muscles until ne'eded at some later time when glucose levels are low. If b!?od glucose levels are low, then epinephrine and glucagon horniones are secreted to stimulate the conversion of glycogen to glucose. This process is called glycogenolysis (catabolism). If glucose is needed immediately upon entering the cells to supply energy, it begins the metabolic process called glycolysis (catabolism). The end products of glycolysis are pyruvic acid and ATP. Since glycolysis releases relatively little ATP, further reactions continue to convert pyrlivic acid to acetyl CoA and then citric acid in the citric acid cycle. 'The majority of the ATP is made from oxidations in the citric acid cycle in connection with the electron transport chain.