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The patient with acute gastrointestinal problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Rebecca Maindonald, Adrian Jugdoyal
The major processes of digestion and absorption of nutrients occur in the small intestine. Its length of approximately 3 metres provides a large surface area for these functions, which are further enhanced by the presence of circular folds, villi and microvilli. The circular folds aid absorption, not only by increasing surface area, but by causing the chyme to spiral, rather than move in a straight line as it passes through the small intestine (please see Figure 10.2).
Disorders of the digestive tract
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
The small intestine is divided into three sections. The duodenum extends beyond the pyloric sphincter in the stomach. The common bile duct empties into the duodenum. The duodenum is the primary site of iron and calcium absorption. The height of duodenal villi increases in pregnancy and, along with a longer transit time, enhances greater absorption of these and other substances. The next section of the small bowel is known as the jejunum and is responsible for the absorption of fats, carbohydrates and protein. The last section is the ileum, which is responsible for the absorption of vitamin B12 and bile salts. The surface of the small intestine forms a series of circular folds, which increases the surface area available to absorb nutrients, which is the primary function of the small intestine. The surface has a velvet appearance due to the presence of fine hair-like projections known as villi, where absorption takes place.
Disorders of the digestive tract
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
The small intestine is divided into three sections. The duodenum extends beyond the pyloric sphincter in the stomach. The common bile duct empties into the duodenum. The duodenum is the primary site of iron and calcium absorption. The height of duodenal villi increases in pregnancy and, along with a longer transit time, enhances greater absorption of these and other substances. The next section of the small bowel is known as the jejunum and is responsible for the absorption of fats, carbohydrates and protein. The last section is the ileum, which is responsible for the absorption of vitamin B12 and bile salts. The surface of the small intestine forms a series of circular folds, which increases the surface area available to absorb nutrients, which is the primary function of the small intestine. The surface has a velvet appearance due to the presence of fine hair-like projections known as villi, which are where absorption takes place.
Panax quinquefolium saponin liposomes prepared by passive drug loading for improving intestinal absorption
Published in Drug Development and Industrial Pharmacy, 2020
Bing Zhang, Wenli Pan, Yaxin Deng, Haibing He, Jingxin Gou, Yanjiao Wang, Yu Zhang, Tian Yin, Dongchun Liu, Xing Tang
The absorption of PQS in each intestine segment was different, which might be related to the distribution and morphological characteristics of small intestine villi in each segment of the small intestine. The small intestine villi were villous protrusions on the circular folds on the inner surface of the small intestine wall, and were the main site for the small intestine to digest and absorb nutrients and drugs. From the distribution point of view, the small intestine villi began to appear in the duodenum, and were most dense at the end of the duodenum and the jejunum, and gradually decreased downward to disappear below the middle intestine. From the morphological point of view, the small intestine villi in the duodenal segment were wide and tall and leaf-shaped, more like fingers in the jejunum segment, and thin and short in the ileum segment [42]. Therefore, the physiological distribution and morphological characteristics of the small intestine villi determined the absorption capacity of the small intestine, which also explained why PQS-Sol and PQS-Lips had the worst absorption in the ileum.
Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice
Published in Gut Microbes, 2020
Mengfei Peng, Zajeba Tabashsum, Puja Patel, Cassandra Bernhardt, Chitrine Biswas, Jianghong Meng, Debabrata Biswas
To address concerns from the host’s point of view, the maintenance of intact and operative gut intestine physiological condition is crucial in both metabolism and symbiotic intestinal microbiota composition.5,45–47 In our study, LC+mcra and its byproduct CLA prevented ST-induced elimination of goblet cells, villi, and microvilli as well as the inflammatory infiltrations between circular folds in cecum, which maintained the overall functions in terms of intestinal nutrients absorption and profoundly raised the survival rate (0 death) in mice. As a matter of fact, CLA has also been previously tested in colitis and inflammatory bovine disease recovery and showed significant gut health benefits,48,49 but the specific mechanism was not explained. Here, our findings based on CLA are in support of these researches and suggest a protective mechanism from both bacterial colonization and host histology sides.
Targeting the intestinal lymphatic system: a versatile path for enhanced oral bioavailability of drugs
Published in Expert Opinion on Drug Delivery, 2018
Renuka Suresh Managuli, Sushil Yadaorao Raut, Meka Sreenivasa Reddy, Srinivas Mutalik
Small intestine consists of four tissue layer: i) innermost mucosa layer which is involved in nutrients absorption from partly digested food (chyme); ii) middle submucosa layer consists of nerves, blood, and lymphatic vessels which transport nutrients from intestine to rest of the body; iii) down to submucosa layer exists the muscularis layer consisting of several layers of smooth muscle tissues which aids in contraction of small intestine, and iv) outermost is the serosa layer which along with the mesentery surrounds the intestine. The interior wall of the small intestine is in the form of circular folds and the epithelial lining of the mucosal layer is protruded into finger like projections known as villi (singular: villus). Around 20,000 villi are present per square inch of mucosa [13]. The epithelial cells in the small intestine comprising enterocytes (absorptive cells), goblet cells, paneth cells, enteroendocrine cells, and tuft cells are held together by tight junctions forming a barrier and they possess a brush border surface onto them known as microvilli [14]. The circular folds and projections (villi and microvilli) increase the intestinal surface area thereby offering maximum contact between epithelial cells and chyme for optimum absorption of nutrients.