China
Africa
Explore chapters and articles related to this topic
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).
The Digestive (Gastrointestinal) System and Its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
Peristaltic contractions propel chyme from the duodenum, through the jejunum and ileum, sections of the small intestine approximately nine and thirteen feet in length respectively. During this process, all products of carbohydrate, fat, and protein digestion, along with most of the electrolytes, vitamins, and water, are absorbed. Bile salts and vitamin B12 are normally not absorbed until they reach the ileum.
Digestive and Metabolic Actions of Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
The small intestine in humans is 20–25 feet in length and has a diameter of 1 inch. Extrinsic innervation to the small intestine is provided by parasympathetic nerve fibers from the vagus nerve and sympathetic nerve fibers from the thoracic splanchnic nerve. Intrinsic innervation comes from the enteric dopaminergic system, covered in detail in Section 8.3.5. The superior mesenteric artery is the main arterial supply to the intestine. Veins, running parallel to the arteries, drain into the superior mesenteric vein. Nutrient-rich blood from the small intestine is carried to the liver via the hepatic portal vein.
Naringenin modulates Cobalt activities on gut motility through mechanosensors and serotonin signalling
Published in Biomarkers, 2023
Adeola Temitope Salami, Ademola Adetokubo Oyagbemi, Moyosore Victoria Alabi, Samuel Babafemi Olaleye
The small intestine, is a part of the gastrointestinal tract responsible for nutritional absorption (from food), immunologic and endocrine functions (Denbow 2015, Mark and Bouwmeester 2017) besides motility. Motility within the small intestine enhances mixing, transit of secretions and digested contents from the stomach, and removal or ridding of ingested harmful or toxic substances not absorbed. Hunt et al. (1985) demonstrated that gastric emptying is hinged on the volume, composition, osmolality and caloric density of food ingested which is coordinated by the pyloric sphincter and duodenum activities. Mechanosensors (Alcaino et al. 2017) found along the small intestine aid these activities; examples of these include epithelial cells such as myenteric neurons, interstitial cells of Cajal, smooth muscle, enterochromaffin cells, glia, etc. The digestive system is propelled by the enteric nervous system (ENS) while gut hormones also regulate functioning of the intestine such as motility, secretion, cell proliferation, digestion and absorption (Ma and Lee 2020). Gastric emptying is regulated by its’ inhibitory and excitatory hormones which are also released from both the intestine and pancreas thus mediating or relating food intake, satiety, energy metabolism to gastric emptying (Goyal et al. 2019).
Hydrophobic ion pairing with cationic derivatives of α-, ß-, and γ-cyclodextrin as a novel approach for development of a self-nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin
Published in Drug Development and Industrial Pharmacy, 2021
Masoomeh Bahiraei, Katayoun Derakhshandeh, Reza Mahjub
First, rats were anesthetized within overdose of ether, and the abdomen was opened by a midline incision. The whole of the small intestine was removed, and a segment between the upper end of the duodenum and the lower end of the ileum was quickly cut, and the mesentery was manually separated. The small intestine was carefully washed with Normal saline solution using a syringe equipped with a blunt end. To minimize the transport variability of segments, the jejunum segment of the small intestine from each animal was used. Then after, intestinal segments (5 ± 0.5 cm) were everted using a stainless-steel rod, washed again in cold saline to remove any adhering material and tied with cotton thread [41]. The everting procedure was performed carefully and slowly in a manner that any injury to the mucosal layer was avoided. In the end, to make an empty gut sac and prevent rapid peristaltic muscular contraction, a weight (1 g) was fixed and tied to the end of the everted gut segment [41].
Healthy Intestinal Function Relies on Coordinated Enteric Nervous System, Immune System, and Epithelium Responses
Published in Gut Microbes, 2021
Fatima B. Saldana-Morales, Dasom V. Kim, Ming-Ting Tsai, Gretchen E. Diehl
The primary role of the gastrointestinal (GI) tract is to digest and absorb nutrients and excrete waste products after digestion1. The small intestine is tasked with nutrient digestion and absorption2 and the large intestine with absorption of water, electrolytes, and water-soluble vitamins.3 Healthy function of the intestine is supported by multiple systems, including the epithelium, nervous system, and immune system.4–6 The epithelium forms a tight, flexible, and dynamic physical barrier that allows for nutrient absorption. The immune system promotes a hospitable environment for commensal microorganisms, defends against pathogens, and supports epithelial and neuronal functions including survival and repair. The enteric nervous system coordinates absorption, muscle control, and peristalsis and further supports immune and epithelial functions. In the steady state and after injury or infection, these systems sense common signals to promote digestion, support tissue growth, clear pathogens, and repair tissue damage.7–9 This review will highlight both the individual responses against common signals by the epithelial, immune, and neuronal compartments of the gut as well as outline how these signals converge to ensure proper tissue function.