Pyloric sphincter

The food, now in a liquid form known as chyme, passes through the pyloric sphincter into the duodenum, where stomach acid is neutralized. There is wide variation in lengths of the components of the small intestine (i.e., duodenum, jejunum, and ileum) between individuals (Table 98-1). Most absorption of digested carbohydrate and protein occurs within the jejunum. Most fat absorption occurs within the jejunum and ileum. In the small bowel, breakdown of macronutrients (i.e., carbohydrate, protein, and fat) occurs both within the lumen of the gut and at the intestinal mucosal membrane surface. The absorptive units on the intestinal mucosal membrane are infoldings known as... 

Postpyloric feeding Delivery of nutrients via a tube placed with its tip past the pyloric sphincter separating the stomach from the duodenum. 

Gastrointestinal sphincters are formed where the circular layer of smooth muscle is thickened. Sphincters occur at several points along the tract. Their function is to limit the movement of food materials from one region to another. For example, the pyloric sphincter found between the stomach and duodenum of the small intestine plays an important role in limiting the rate of gastric emptying. Sphincters undergo tonic contractions that may be sustained for minutes or hours. 

Increases tone and amplitude of gastric contractions, relaxes the pyloric sphincter and the duodenal bulb, and increases peristalsis of the duodenum and jejunum, possibly by sensitizing tissues to the action of acetylcholine, resulting in accelerated gastric emptying and intestinal transit... 

Pyloric sphincter hypertrophy, enlarged stomach Huang et al. (1993)... 

To understand the special constraints of herbivorous fishes, it helps to first understand the carnivore digestive process.40412 Carnivorous fishes consume food in which nutrients are generally readily available and of high quality (protein rich). In these fishes, food is usually broken down in the stomach through a combination of muscular contractions of the stomach wall and enzymatic action in an acid medium. Breakdown products are expelled from the stomach through the pyloric sphincter into the intestine in a process called gastric evacuation. Digestion and food absorption are completed in the intestine.40412... 

CCK influences gastric motility, movements of the gastrointestinal tract that influence the passage of food. CCK stimulates contraction of the pyloric sphincter or pylorus. A sphincter is a ring of muscles that controls the rate of passage of material through an opening or channel in the body. The pylorus is located at the... 

The fasting stomach pH is about 2 to 6. In the fed state, the stomach pH is about 1.5 to 2, due to hydrochloric acid secreted by parietal cells. Stomach acid secretion is stimulated by gastrin and histamine. Mixing is intense and pressurized in the antral part of the stomach, a process of breaking down large food particles described as antral milling. Food and liquid are emptied by opening the pyloric sphincter into the duodenum... 

Scheme 2 Diagram of pyloric ring in motor quiescent phase. W, width H, height DB, duodenal bulb PA, pyloric aperture PSC, pyloric sphincteric cylinder. (From Ref...

Secretin is a 27-amino-aeid polypeptide that is slruciurally. similar to glucagon. The presence of acid in the. small intestine is the most important physiological stimulus for the secretion of secretin. The primary action of secretin Ls on pancreatic acinar cells that regulate the secretion of water and bicarbonate. Secretin also promotes the secretion of pancreatic enzymes, to a lesser extent. Secretin inhibits the release of gastrin and. therefore. ga.slric acid. It also increases stomach-emptying time by reducing the conlraction of the pyloric sphincter. ... 

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