Flashcards in Principles of Gastrointestinal Regulation Deck (89)
What are the main functions of the gastrointestinal tract?
-To absorb nutrients and water into circulation
-To participate in the excretion of waste substances.
What are the 5 main physiological processes that the GI tract participates in?
How does the duodenum deal with the high acidity of the substances coming in from the stomach?
It has a high amount of bicarbonate in order to neutralize the acid
What causes motility in the digestive system?
It is a consequence of contractions of layers of smooth muscle cells in the GI tract.
What is the function of secretion in the GI tract?
It is the release of enzymes, biological detergents, mucus, ions and water in the GI lumen
What is the function of digestion?
It breaks down food so that it can be absorbed for nutrients by the body
What are the 3 saccharides that the body can absorb?
What is the function of absorption in the GI tract?
Process by which nutrients, electrolytes and water are absorbed from the GI lumen into the bloodstream
What is the function of excretion in the GI tract?
Stores and excretes waste substances from the body ranging from cholesterol to drug metabolites
What is the relation of the GI tract to the immune system?
The GI tract is open to the external environment and as a result it is exposed to many organisms so it must have immune cells to protect the body non specifically
What is the flow of the GI tract?
What is the function of the upper esophageal sphincter?
It is between the pharynx and the esophagus and it keeps food out of the trachea
What is the function of the lower esophageal sphincter?
It is between the esophagus and the stomach and it keeps acid out of the esophagus
What is the function of the pyloric sphincter?
It is between the stomach and the duodenum and it keeps acid out of the duodenum
What is the function of the sphincter of Oddi?
Controls the flow of bile and pancreatic fluid
What is the function of the ileocecal sphincter?
Prevents back flow into the small intestine
What are the major arteries of the splanchnic region?
What does the celiac artery supply?
What does the superior mesenteric artery supply?
What does the inferior mesenteric artery supply?
What is unique about the venous drainage of the GI tract?
It does not drain into the systemic circulation and instead goes into the portal system
What is the advantage of the portal venous system?
It allows blood to go through the liver for detoxification as an additional defense mechanism
What is the importance of the lymphatic drainage in the GI tract?
Lipids and lipid soluble molecules cannot cross the capillaries so they are drained via the thoracic duct
What are the layers of the GI tract from innermost to outermost?
What is the role of absorptive enterocytes in the mucosal epithelium?
Important in digestion and absorption
What is the role of enteroendocrine cells in the mucosal epithelium?
Release regulatory peptides
What is the role of gastric mucosal cells in the mucosal epithelium?
What is the role of mucin-producing cells in the mucosal epithelium?
What cell type is found in esophageal epithelium?