Nurs 251 Pharmacology Module 7 Exam Portage Learning

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Module 77.1: Introduction to GastroenterologyThe organs of the upper gastrointestinal tract (mouth, pharynx, esophagus, stomach, and duodenum) work in conjunction to first digest food and then absorb the nutrients obtained from the digested food. Both the stomach and the upper part of the small intestines (duodenum) release hormones and enzymes that help in this process. When food enters the body, the stomach is triggered to begin releasing gastric juices such as hydrochloric acid (HCl) and an enzyme called pepsin . HCl is released by parietal cells located in the stomach. Due to its acidic nature, HCl aids in the breakdown of food entering the stomach . Pepsin is the primary digestive enzyme found in the stomach. Pepsin is responsible for the catabolism (breaking down) ofproteins into polypeptides . There are three major stimulators that affect the release of gastric juices: Acetylcholine (ACh), gastrin, and histamine . First, the ingestion of food stimulates ACh to bind to its target receptors , stimulating the release of pepsin, gastrin, histamine, and HCl from chief cells, G cells, enterochromaffin like (ECL) cells, and parietal cells respectively . Gastrin then binds to its target receptors on ECL and parietal cells which s timulates the release