Enzymes, Chemicals and Hormones associated with the Human Digestive System

MOUTH
Enzyme, Chemical, Hormone or Cell / Enzyme, Chemical, Hormone or Cell / Important Information
Salivary Amylase / enzyme / Found in salivathat catalyzes thehydrolysis(breaking down) ofstarch, glycogenand relatedpolysaccharidesinto more simple and readily usable forms of sugar.
Ptyalin / enzyme / A form of amylase found in the saliva of humans and some other animals; converts starch into simple soluble sugar
Betaine / Chemical / Maintains cell fluid balance as osmolytes (dehydration, dry mouth); protects cells, proteins, and enzymes from environmental stress (eg, low water, high salinity, or extreme temperature)
Bromelain / enzyme / Found in pineapple, that breaks down protein and is used as a meat tenderizer; Anti-inflammatory agent
Lysozyme / enzyme / Found in saliva (and tears) and catalyzes the destruction of the cell walls of certain bacteria.
STOMACH
Enzyme, Chemical, Hormone or Cell / Enzyme, Chemical, Hormone or Cell / Important Information
Parietal Cells / cell / Are the stomach epithelium cells which secrete gastric acid (HCl); Primarily secreted in response to ingested protein or fat; stress also may stimulate acid output; also secrete intrinsic factor absorption of vitamin B12and the normal development of red blood cells Pernicious anemia may be caused by the absence of intrinsic factor.
Chief Cells / cell / Also called zymogenic cell.Any one of the columnar epithelial cells or the cuboidal epithelial cells that line the gastric glands and secrete pepsinogen which are needed for the digestion of proteins
Mucous neck or Pit Cells / cell / Involved in mucous production and are replaced every 2–4 days. This high rate of turnover is a protective mechanism designed to protect the epithelial lining of the stomach from both the action of pepsin and the acid produced by parietal cells;
G Cells / cell / A gastrin-producing cell found in the antrum (initial portion of the pyloric portion of the stomach) of the stomach and to a lesser extent in the mucosa of the duodenum
Pepsin / enzyme / R Released in the stomach as pepsinogen (zymogen - an inactive substance that is converted into an en enzyme when activated by another enzyme); the release of HCl stimulates the release of the basic m form of pepsin; when pepsinogen is exposed to HCl in the stomach the pepsinogen unfolds and pe breaks into pepsin; breaks down proteins into smaller polypeptides
HCl / chemical / ThThe pH of gastric (stomach) acid should normally be between 1.5-3.5, HCl denatures proteins;
Aactivates the conversion of pepsinogen to pepsin; acts as antiseptic in the stomach; allows for improper mineral absorption as it assists in ionizing minerals
Intrinsic Factor / Chemical
glycoprotein / A A substance secreted by the stomach that enables the body to absorb vitamin B12. It is a fd glycoprotein
Gastrin / hormone / Gastrin is a major physiological regulator of gastric acid secretion.It also has an important growth-promoting influence on the gastric mucosa. Gastrin is synthesized in G cells, which are located in gastric pits, primarily in the antrum region of thestomach. Anticipation of food, stomach stretching (rugae), presence of partially digested food – stimulates the secretion of gastric juices rich in pepsin and HCl which aid in digestion.