Dissertations / Theses on the topic 'Digestive system'
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Monteiro, Emiliano Carneiro. "O sistema digestivo do \"bicho-pau\" Phibalosoma phyllinum (Phasmida, Phasmatidae): uma análise morfológica, fisiológica e bioquímica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-24082012-092811/.
Full textThis work presents a detailed morphofunctional study of the digestive system of Phibalosoma phyllinum (Phasmida, Phasmatidae). From an anatomical point of view, the digestive system of this insect is formed by a foregut, a midgut and a hindgut. The foregut is composed by the buccal cavity (where the salivary gland\'s duct open), a pharynx and an aesophagus that ends in the proventriculus. The midgut consists of a tubular ventriculus and it can be divided in three regions: the anterior ventriculus (AV), the middle ventriculus (MV), and the posterior ventriculus (PV) which can be further subdivided in its proximal (PVI), and distal (PVII) sub-regions. The presence of a complex system of ventricular appendices was observed in the PVI sub-region, which are formed by protuberances, in the external ventricular surface, and by blind-ended canaliculi, which are connected to the protuberances. The hindgut is divided into an ileum and a rectum that ends in the anus. Seen by light microscopy, the foregut is made up by a simple epithelium, which is composed of squamous cells and covered by a cuticle layer. Through the whole foregut the cuticle forms spines. The proventriculus is formed by a simple muscular valve that separates the foregut from the midgut. The midgut itself is formed by a simple epithelium, which is made up of three different cell types: columnar cells (enterocytes), which are the main site of enzyme production and secretion, and nutrient absorption, the regenerative cells, which are clustered in nidi at the basal portion of the epithelium, and the endocrine cells. The ventricular appendices, in turn, are formed by a simple epithelium that is continuous with the ventricular epithelium. Cells from the protuberances are large showing a round shape, while canalicular cells are short, and very similar to the ones presented in the Malpighian tubules. In the transition between the midgut and the hindgut, several Malpighian tubes branch off. The hindgut is formed by a simple epithelium, lined by cuticle. The ventricular lumen is covered by a tubular structure called peritrophic membrane whose presence was confirmed by fluorescence microscopy, using chitin-binding lectin WGA (wheat germ agglutinin) coupled with FITC (fluorescein isothiocyanate). In order to identify specific ventricular regions where water absorption and secretion through the epithelium take place, physiological experiments, using amaranth dye solution were performed. This solution was either orally administered, or injected in the hemolinph of both fed and starved insects. These experiments revealed that, both in fed and starved animals, the AV is the main site of water absorption, whereas the Malpighian tubules are the main sites of water secretion into the ventricular lumen. Ultrastructural analysis showed that enterocytes present an apical surface modified into well-developed microvilli. In their lateral surface, the adjacent plasma membranes are linked by desmosomes and smooth septate junctions. The basal plasma membrane shows several infoldings, forming a labyrinth of channels with associated mitochondria. In the AV and MV, these infoldings present a limited number of openings to the basal lamina, which indicates a greater water absorption potential of these regions from the gut lumen. In the PV cells, the number of openings is greater, indicating that these regions may be involved in water secretion (although occurring in levels that are undetectable through dye experiments). Regenerative cells nidi, in turn, can be observed in the basal portion of the epithelium throughout the midgut. This cell type shows characteristics of undifferentiated cells, such as large nuclei and few organelles. Endocrine cells are confined to the basal portion of the epithelium. Both the ventricular canaliculi and the Malpighian tubules are made up by cuboidal cells with modified apical microvilli bearing mitochondria in their interior, and basal plasma membrane forming a labirinth with many well developed infolds and openings to the basal lamina, as well as many associated mitochondria. An intense secretory activity was observed along the entire midgut. Large amounts of rough endoplasmic reticulum, well developed Golgi areas were observed in the enterocytes. In the AV and MV a large number of secretory vesicles could be observed concentrated in the apical portion of the cells, and their contents are probably eliminated by a merocrine mechanism. Along the PV, secretory vesicles are apparently absent but microvilli display dilated tips frequently showing small vesicles in their interior. This observation may indicate the occurrence of a microapocrine secretory mechanism in this ventricular region. The enzymes amylase and trypsin were immunolocalized in the cells from the AV and MV. In these regions, the two enzymes were detected in Golgi areas, secretory vesicles and in the the ventricular lumen, between the microvilli. Thus, both enzymes seem to be produced and eliminated through the same secretory pathway. Luminal pH measurements revealed a great variation of the pH along the intestine of this species. While in its anterior region the pH is acid (5,3 in the foregut and 5,6 in the AV), it becomes gradually alkaline towards the posterior regions (6,3 in the anterior MV, 8,0 in the posterior MV, 9,1 in the PVI and 8,5 in the PVII); in the hindgut the pH is neutral (7,3). The effect of the pH on amylase and trypsin activities was also measured. It was determined that trypsin\'s optimal pH was 9,0, and amylase\'s optimal pH was 5,0. Biochemical assays of digestive enzymes revealed the presence of amylase and trypsin in the luminal contents, mainly in the foregut and AV. In spite of that, it is possible that trypsin\'s activity is greater in the MV and PV, where the alkaline luminal pH matches the optimal pH for this enzyme. Chymotrypsin is also present in the lumen of the foregut and AV, but, unlike amylase and trypsin, its major activity is found in the AV. Aminopeptidase is found in the ventricular epithelium, mainly in the MV and PV, and maltase is detected associated with the microvillar glicocalix in the AV and PV regions. The hindgut showed low levels of digestive enzyme excretion, both in fed and starved animals, suggesting that these enzymes are recovered during the digestive process. Thus, these results point to the occurrence of an endo-ectoperitrophic circulation of digestive enzymes in both fed and starved animals, in which the AV is the main absorption site of water and the Malpighian tubules, the main secretion site. Initial carbohydrates digestion should occur in the foregut and in the AV, in the endoperitrophic space, whereas its final digestion should take place in the epithelial surface. Protein digestion should take place in the MV and in the PV; initial digestion should occur in the luminal endoperitrophic space, whereas final digestion takes place in the epithelial surface of these regions. Carbonic anhydrase assays revealed a high activity of this enzyme in the ventricular appendices. This fact, along with the morphological similarity between ventricular canaliculi and Malpighian tubules suggest that the canaliculi and the Malpighian tubules are homologous structures. Along the evolutionary process, the canaliculi probably acquired the capability to promote the alkalization of the PV lumen (mainly in the PVI region) thus affecting the digestive process
Hames, C. A. C. "The digestive system and metals in terrestrial isopods." Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234697.
Full textMan, Siu-yin. "Adrenomedullin in the rat digestive system response to starvation /." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B32032298.
Full textMan, Siu-yin, and 文小燕. "Adrenomedullin in the rat digestive system: response to starvation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32032298.
Full textFilietáz, Carlos Felipe Tasso. "Padrões de especificidade e expressão das lipases digestivas durante o desenvolvimento e o processo infeccioso no mosquito Aedes aegypti." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-23022017-120752/.
Full textThe Aedes aegypti borne diseases yellow fever, dengue fever, chinkungunya and zica are important public healthy problems. The digestion and absorption of nutrients are performed in the digestive system, which is also an external environment interface that allows the infection by pathogenic microorganisms. The presence of two digestive lipases were identified by qPCR, L-Aa7051 in the larval phase and L-Aa7055 in the adult female. The lipase sequences were grouped in the neutral family, and exhibit alterations in residues involved in specificity, lid domain and β9 loop. The recombinant L-Aa7055 was expressed in the insoluble fraction, and show activity after a renaturation process. We notice that the expression levels of L-Aa7055 are reduced by 30% in the Plasmodium gallinaceum infection and were not affected by serotype 2 dengue virus (DENV2). The lipid digestion is important in the larval phase, with higher transcript levels. New studies will be necessary to the complete understanding of lipase contribution in the infectious process.
Akhlaq, Maham. "Investigation of Cten signalling and regulation in colorectal cancer." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32802/.
Full textJain, Kamini. "Prevention of treatment related adverse effects in cystic fibrosis." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/55105/.
Full textAlsulaiman, Abdullah. "Investigation of the role of CD24 in metastatic colorectal cancer." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/55401/.
Full textCouch, Daniel. "The actions of cannabidiol and palmitoylethanolamide on inflammation and permeability of the gut." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/51804/.
Full textAsiri, Abdulaziz. "Investigations into the role of Cten signalling in colorectal cancer." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52233/.
Full textDe, Rosa Antonella. "Oestrogen receptors in oesophageal cancer." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52399/.
Full textMaitra, Rudra Krishna. "Evolving new drug treatments for faecal incontinence." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/44517/.
Full textSaunders, John. "Ex vivo modelling of oesophago-gastric cancer." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/47574/.
Full textBoereboom, Catherine L. "Determining the feasibility and effectiveness of high intensity interval training in preoperative colorectal cancer patients." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/47342/.
Full textPalaniyappan, Naaventhan. "Quantitative magnetic resonance imaging in evaluating haemodynamic changes in portal hypertension." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/45274/.
Full textVitish-Sharma, Parveen. "The effect of Trendelenburg positioning in laparoscopic colorectal surgery on intraocular pressure and cognitive function." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/48966/.
Full textProkopchuk, O. V. "Criteria for digestive system dysfunction in newborns with perinatal pathology." Thesis, БДМУ, 2022. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/19808.
Full textLam, Ching Yin. "Biomarkers to assess an anti-inflammatory treatment for irritable bowel syndrome : mast cell assays and magnetic resonance imaging." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28803/.
Full textTobias, Amanda Jane. "Gastrin interactions which impact upon gastric, colonic, pancreatic and oesophageal carcinogenesis." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11348/.
Full textAlbasri, Abdulkader. "An investigation of the role of C-terminal tensin-like (Cten) gene in colorectal cancer." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12055/.
Full textBrown, Matthew. "The expression of Toll-like receptors-2 and-4 by human crypt intestinal epithelial cells, intestinal myofibroblasts and putative intestinal stem cells in inflammatory bowel disease." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/13437/.
Full textMirams, Gary R. "Subcellular phenomena in colorectal cancer." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/10567/.
Full textChen, Liqiong. "The development of a novel in vitro model of human liver for the study of disease pathogenesis." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11020/.
Full textFleming, Catherine Mary. "The epidemiology of cirrhosis and abnormal liver function in the general population of the UK." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11371/.
Full textCrooks, Colin J. "The epidemiology of upper gastrointestinal bleeding." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13394/.
Full textParsons, Caron Saeko. "The development of a patient reported outcome measure and imaging modalities in the evaluation of haemorrhoidal disease." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/28466/.
Full textMannath, Jayan. "Endoscopic multimodal imaging in Barrett's oesophagus." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/28688/.
Full textHammond, John Stotesbury. "Scaffolds for liver tissue engineering : in vitro co-culture & in vivo release." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/12556/.
Full textStevenson, Diane J. "P2X7, inflammation and gastrointestinal disease." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/28897/.
Full textCrusz, S. A. "Lectin-mediated biofilm maturation, quorum sensing and Pseudomonas aeruginosa infections in cystic fibrosis." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10734/.
Full textRoyal, E. L. "Interplay between hypoxia and gastrin in gastrointestinal cancer." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10805/.
Full textAbdul, Rahim Roslina. "Molecular mechanism underlying the pathogenesis of NAFLD and NASH." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12074/.
Full textMaxwell-Armstrong, Charles Alan. "Studies using the anti-idiotypic monoclonal antibody 105AD7 in patients with advanced and primary colorectal cancer." Thesis, University of Nottingham, 1998. http://eprints.nottingham.ac.uk/14137/.
Full textCard, Timothy R. "A contribution to knowledge of the aetiology and indirect impact of inflammatory bowel diseases : (based upon analysis of routinely and semi-routinely available data)." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/12445/.
Full textGemmill, Elizabeth H. "Minimally invasive gastro-oesophageal surgery for cancer : current evidence and practice." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/55424/.
Full textIngram, Richard J. M. "Duodenal ulcer promoting gene : effects on the pathophysiology of Helicobacter pylori infection and the host immune response." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42105/.
Full textHam, Karom Hersh Abdul. "Investigate tumour heterogeneity and genetic pathways in colorectal cancer." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42487/.
Full textOnyido, Emenike K. "Mechanisms and roles of FLYWCH1 in colorectal cancer." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42558/.
Full textShaheen, Sameerah. "Roles & mechanisms of NANOG-mediated drug resistance in human colorectal cells." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43364/.
Full textPoghosyan, Anna. "Molecular mechanisms of enhanced expression of the chemokine interleukin 8 (CXCL8) in cystic fibrosis (CF) airway epithelial cells." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27801/.
Full textSaini, Francesca. "Role of the Hedgehog pathway in the pancreatic tumour microenvironment." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27738/.
Full textGarsed, Klara C. "Predicting the response to Ondansetron, a 5HT3 receptor antagonist, in irritable bowel syndrome with diarrhoea : the utility of clinical features and objective biomarkers." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14332/.
Full textDainty, Andrew David. "The cognitive behavioural treatment of irritable bowel syndrome : feasibility of a nurse delivered model of guided self-help." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/35537/.
Full textAl-Masmoum, Hussain. "An investigation of chromosome 20q13 amplification in colorectal cancer." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/36938/.
Full textMahdi, Adnan Hammad. "The structure and innervation of the sphincters in the large intestine of the domestic duck (Anas platyrhynchos)." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/29864.
Full textFindlay, John Mitchell. "Precision staging and management of Barrett's oesophagus and oesophageal cancer : genomic, imaging and pathological biomarkers." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38037/.
Full textCanavan, Caroline. "Using real world data to generate health economic models : a worked example assessing the cost-effectiveness of referral to gastroenterology for irritable bowel syndrome in the UK." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32666/.
Full textKeeler, Barrie D. "Investigation of patient blood management in colorectal surgery." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33457/.
Full textVaradhan, Krishna Kumar. "The mechanistic basis of metabolic response to surgery and postoperative insulin resistance in patients having abdominal surgery." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29095/.
Full textMolokwu, Anuri Joy. "Assessment of dysphagia in people with Parkinson's disease, multiple sclerosis and muscular dystrophy." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29048/.
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