The Digestive System

The Digestive System

Vocabulary: Digestive System

Peristalsis | The wavelike muscular contractions of the digestive tract by which its contents are forced to move onwards. It is performed by the ring-like muscles of the walls of the esophagus, the stomach and the intestines. |

Bolus | The food mass that crosses the esophagus after having undergone a first digestive stage in the mouth. |

Chyme | The fluid food mass that is produced in the stomach when the bolus undergoes a second digestive stage. |

Chyle | The very fluid food mass that is produced in the duodenum when the chyme undergoes the third digestive stage. |

Enzymes | They are special proteins that behave as catalysts, i.e., they accelerate each and every chemical reaction in your body; otherwise, those chemical reactions wouldn't take place, or would do at a very slow pace. Enzymes are very specific and each one can catalise only one chemical reaction: for instance, the only thing that salivary amylase can do is breaking the starch into maltose. |

Digestive enzymes | The enzymes that break down the long molecules in the foods into much smaller ones that can later on be absorbed into the bloodstream. The main ones are the amylases (break down carbohydrates into sugars), the proteases (break down proteins into aminoacids) and the lipases (break down the lipids into glycerol and fatty acids). They come in the following digestive juices: the saliva, the gastric juice, the pancreatic juice and the intestinal juice. |

Bile | One of the five digestive juices. It is produced by the liver, stored in the gall-bladder, and it is greenish. It is necessary mostly not to carry digestive enzymes to the duodenum, but to transport bile salts to the duodenum. The bile salts are necessary to help the lipids to "dissolve" in the chyle, forming small droplets, easy to be attacked by the lipases. This process is called emulsification. |

Villi | The finger-like folds in the small intestine. They increase...