Search results
Results from the WOW.Com Content Network
Glycogen (black granules) in spermatozoa of a flatworm; transmission electron microscopy, scale: 0.3 μm. Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, [2] fungi, and bacteria. [3] It is the main storage form of glucose in the human body.
Glycogenesis is the process of glycogen synthesis or the process of converting glucose into glycogen in which glucose molecules are added to chains of glycogen for storage. This process is activated during rest periods following the Cori cycle , in the liver , and also activated by insulin in response to high glucose levels .
Humans lack the cellulases to digest the carbohydrate cellulose which is a beta-linked glucose polymer. Some of the preceding endogenous enzymes have pharmaceutical counterparts ( pancreatic enzymes ) that are administered to people with exocrine pancreatic insufficiency .
In humans, insulin is made by beta cells in the pancreas, fat is stored in adipose tissue cells, and glycogen is both stored and released as needed by liver cells. Regardless of insulin levels, no glucose is released to the blood from internal glycogen stores from muscle cells.
The glycogen debranching enzyme, in humans, is the protein encoded by the gene AGL. [5] This enzyme is essential for the breakdown of glycogen , which serves as a store of glucose in the body. It has separate glucosyltransferase and glucosidase activities.
Small amounts of glycogen are found in the kidneys and even smaller amounts in certain glial cells in the brain and white blood cells. The uterus also stores glycogen during pregnancy to nourish the embryo. [17] Glycogen is composed of a branched chain of glucose residues. It is primarily stored in the liver and muscles. [21]
In addition to glycogen breakdown with the glycogen debranching enzyme and the glycogen phosphorylase enzyme, cells also use the enzyme acid alpha-glucosidase in lysosomes to degrade glycogen. A deficiency of an involved enzyme results in: Accumulation of glycogen in the cells; Lack of cellular energy negatively affects the involved organs
The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.