In the adult ruminant, abomasal emptying is a permanent phenomenon depending upon meal volume. Intradian rhythm involving the motor pattern of the duodenum and circadian rhythm of unknown origin modulate the transpyloric flow rate. The fundic tone, antro-duodenal coordination and pyloric resistance regulate gastric outflow. The break-like function of the pyloric resistance involves chyme viscosity. Transpyloric flow rate is controlled by a hierarchy of extrinsic and intrinsic mechanisms triggered at the duodenal level. The vagus permanently inhibits the motility of the abomasum. A similar relationship is observed between the pyloric sphincter and duodenal motility. Removal of the pyloric ring leads to an increased food intake.
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J R Soc Interface
January 2024
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Pyloric interventions are surgical procedures employed to increase the gastric emptying rate in gastroparesis patients. In this study, we use an model to investigate the consequences of pyloric intervention on gastric flow and emptying for two phenotypes of gastroparesis: antral hypomotility and decreased gastric tone. The transpyloric pressure gradient predicted by the model, based on viscous fluid flow equations, is compared against measurements.
View Article and Find Full Text PDFAdv Exp Med Biol
January 2023
Gastroenterology Unit, Flinders Medical Centre & College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.
This chapter reviews data on the pathways by which luminal, mainly duodenal, chemoreceptors modulate gastro-pyloro-duodenal motor function to control emptying of nutrients into the small intestine. The vagus mediates proximal gastric relaxation caused by nutrient stimulation of duodenal/jejunal mucosal chemoreceptors. Modulation of the spatial patterning and inhibition of antral contractions during duodenal chemoreceptor activation are somewhat conflicting: both vagal control and ascending intramural nerves appear to play a role.
View Article and Find Full Text PDFNeurogastroenterol Motil
August 2022
Neurogastroenterology & Motility Unit, Gastroenterology Department, Great Ormond Street Hospital for Children, London, UK.
Background/objectives: Gastric emptying (GE) requires precise antropyloroduodenal coordination for effective transpyloric flow, the mechanisms of which are still unclear. We aimed to correlate gastric antral function assessed by antroduodenal manometry (ADM) with GE scintigraphy (GES) for liquid feeds in children with suspected gastrointestinal dysmotility.
Methods: Children who underwent both ADM and GES over a five-year period were reviewed.
J Theor Biol
January 2021
Department of Biotechnology and Medical Engineering, NIT Rourkela, Odisha 769008, India. Electronic address:
A theoretical model of the pyloric channel, approximated as a two-dimensional tube with sinusoidal corrugation, is developed to estimate the degree of resistance offered by the pylorus to transpyloric flow (gastric emptying and duodenogastric reflux) in the viscous regime. Study indicates that the resistance of the channel depends on pressure gradient, flow behavior index and channel diameter. Flow is majorly determined by the extent of luminal opening; since they scale to fourth power of the diameter for Newtonian flow, with the exponent being higher for pseudoplastic and lesser in case of dilatants relative to Newtonian fluid.
View Article and Find Full Text PDFCrit Care
February 2019
Department of Anesthesiology and Operative Intensive Care Medicine, University of Witten/ Herdecke, Medical Center Cologne Merheim, Ostmerheimerstr. 200, D-51109, Cologne, Germany.
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