Search results
Results from the WOW.Com Content Network
Every day, seven liters of fluid are secreted by the digestive system. This fluid is composed of four primary components: ions, digestive enzymes, mucus, and bile. About half of these fluids are secreted by the salivary glands, pancreas, and liver, which compose the accessory organs and glands of the digestive system.
Mucus (/ ˈ m j uː k ə s /, MEW-kəs) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands , although it may also originate from mixed glands, which contain both serous and mucous cells.
Mucus forms a layer (or layers, in the case of the colon) that separates the bulk of the luminal contents from the intestinal epithelium. The mucus consists of a highly glycosylated hydrated gel formed by mucin molecules that are secreted by goblet cells. The mucus prevents large particles from contacting the epithelial cell layer while ...
A peptide hormone, gastrin, produced by G cells in the gastric glands, stimulates the production of gastric juice which activates the digestive enzymes. Pepsinogen is a precursor enzyme ( zymogen ) produced by the gastric chief cells , and gastric acid activates this to the enzyme pepsin which begins the digestion of proteins .
The mucus produced by these cells is extremely important, as it prevents the stomach from digesting itself. [5] Parietal cells produce potent hydrochloric acid, which damages cells. Gastric chief cells produce pepsinogen, which is activated by the acid to form pepsin. Pepsin is a protease that can digest and damage stomach cells.
A variety of maize grows aerial roots that produce a sweet mucus. The Sierra Mixe is a tall variety that survives in poor soils without fertilizer in Oaxaca, Mexico, and the mucilage has been shown to support nitrogen fixation through bacteria that thrive in its high-sugar, low-oxygen environment. [18]
Gastrin is a hormone produced by enteroendocrine G cells in the pyloric glands. [1] All three of these stimulate parietal cells to secrete hydrochloric acid and intrinsic factor. The chief cells secrete pepsinogen in response to gastrin and especially Ach, and ACh also stimulates mucus secretion. [1]
Glycosaminoglycans [1] (GAGs) or mucopolysaccharides [2] are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case of the sulfated glycosaminoglycan keratan, where, in place of the uronic sugar there is a ...