Feeding & Digestion
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A Comparative Study of the Ultrastructure of Microvilli in the Epithelium of Small and Large Intestine of Mice
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PubMed Central A COMPARATIVE STUDY OF THE ULTRASTRUCTURE OF MICROVILLI IN THE EPITHELIUM OF SMALL AND LARGE INTESTINE OF MICE T. M. MUKHERJEE and A. WYNN WILLIAMS From the Electron Microscope Laboratory, the Departlnent of Pathology, the University of Otago Medical School, Dunedin, New Zealand ABSTRACT A comparative analysis of the fine structure of the microvilli on jejunal and colonic epi- thelial cells of the mouse intestine has been made. The microvilli in these two locations demonstrate a remarkably similar fine structure with respect to the thickness of the plasma membrane, the extent of the filament-free zone, and the characteristics of the microfila- ments situated within the microvillous core. Some of the core microfilaments appear to continue across the plasma membrane limiting the tip of the microvillus. The main differ- ence between the microvilli of small intestine and colon is in the extent and organization of the surface coat. In the small intestine, in addition to the commonly observed thin surface "fuzz," occasional areas of the jejunal villus show a more conspicuous surface coat covering the tips of the microvilli. Evidence has been put forward which indicates that the surface coat is an integral part of the epithelial cells. In contrast to the jejunal epithelium, the colonic epithelium is endowed with a thicker surface coat. Variations in the organization of the surface coat at different levels of the colonic crypts have also been noted. The func- tional significance of these variations in the surface coat is discussed. -
A Tissue-Engineered Model of the Intestinal Lacteal for Evaluating Lipid Transport by Lymphatics
ARTICLE A Tissue-Engineered Model of the Intestinal Lacteal for Evaluating Lipid Transport by Lymphatics J. Brandon Dixon,1,2 Sandeep Raghunathan,1 Melody A. Swartz1,2,3 1Institute of Bioengineering, School of Life Sciences, E´ cole Polytechnique Fe´de´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland; telephone: þ41 21 693 9686; fax: þ41 21 693 9670; e-mail: melody.swartz@epfl.ch 2Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 3Institute of Chemical Sciences and Engineering, School of Basic Sciences, EPFL, Lausanne, Switzerland Received 4 September 2008; revision received 21 February 2009; accepted 20 March 2009 Published online 1 April 2009 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/bit.22337 trafficking, but in addition, lymphatics are central to the transport of dietary lipid from the gut. In the small intestine, ABSTRACT: Lacteals are the entry point of all dietary lipids into the circulation, yet little is known about the active enterocytes reesterify the majority of free fatty acids (FFAs) regulation of lipid uptake by these lymphatic vessels, and absorbed from the lumen of the gut into triacylglycerols there lacks in vitro models to study the lacteal—enterocyte which are then incorporated into chylomicrons (Tso and interface. We describe an in vitro model of the human Balint, 1986) and secreted basally to be picked up solely by intestinal microenvironment containing differentiated lacteals, which are blind-ended lymphatic vessels in the Caco-2 cells and lymphatic endothelial cells (LECs). We characterize the model for fatty acid, lipoprotein, albumin, center of each villus (Azzali, 1982; Schmid-Scho¨nbein, and dextran transport, and compare to qualitative uptake of 1990). -
New Large Leptictid Insectivore from the Late Paleogene of South Dakota, USA
New large leptictid insectivore from the Late Paleogene of South Dakota, USA TJ MEEHAN and LARRY D. MARTIN Meehan, T.J. and Martin, L.D. 2012. New large leptictid insectivore from the Late Paleogene of South Dakota, USA. Acta Palaeontologica Polonica 57 (3): 509–518. From a skull and mandible, we describe a new genus and species of a primitive insectivore (Mammalia: Insectivora: Leptictida: Leptictidae). Its large body size and higher−crowned teeth indicate a different feeding ecology from other leptictid insectivores. With evidence of some heavy, flat wear on the molariform teeth, its shift in diet was likely to greater herbivory. Unlike the narrow snout of Blacktops, this new leptictid retains a broad snout, suggesting that small verte− brates were still important dietary components. The specimen was collected from the floodplain deposits of the lower or middle White River Group of South Dakota, which represent the latest Eocene to earliest Oligocene (Chadronian and Orellan North American Land Mammal “Ages”). Key words: Mammalia, Leptictidae, Leptictis, Megaleptictis, Eocene, Oligocene, White River Group, South Dakota, North America. TJ Meehan [[email protected]], Research Associate, Section of Vertebrate Paleontology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, PA 15213, USA; Larry D. Martin [[email protected]], Division of Vertebrate Paleontology, Natural History Museum and Biodiversity Re− search Center, University of Kansas, Lawrence, KS 66045, USA. Received 4 April 2011, accepted 25 July 2011, available online 17 August 2011. Introduction molariform teeth. A fossa in this region at least suggests in− creased snout mobility, but no definitive anatomical argument Leptictida is a primitive order of placental, insectivorous has been made to support a highly mobile cartilaginous snout mammals convergent to extant sengis or elephant “shrews” tip, as in sengis. -
A Non-Bilaterian Perspective on the Development and Evolution of Animal Digestive Systems
Cell and Tissue Research (2019) 377:321–339 https://doi.org/10.1007/s00441-019-03075-x REVIEW A non-bilaterian perspective on the development and evolution of animal digestive systems Patrick R. H. Steinmetz 1 Received: 22 March 2019 /Accepted: 8 July 2019 /Published online: 7 August 2019 # The Author(s) 2019 Abstract Digestive systems and extracellular digestion are key animal features, but their emergence during early animal evolution is currently poorly understood. As the last common ancestor of non-bilaterian animal groups (sponges, ctenophores, placozoans and cnidarians) dates back to the beginning of animal life, their study and comparison provides important insights into the early evolution of digestive systems and functions. Here, I have compiled an overview of the development and cell biology of digestive tissues in non-bilaterian animals. I will highlight the fundamental differences between extracellular and intracellular digestive processes, and how these are distributed among animals. Cnidarians (e.g. sea anemones, corals, jellyfish), the phylogenetic outgroup of bilaterians (e.g. vertebrates, flies, annelids), occupy a key position to reconstruct the evolution of bilaterian gut evolution. A major focus will therefore lie on the development and cell biology of digestive tissues in cnidarians, especially sea anemones, and how they compare to bilaterian gut tissues. In that context, I will also review how a recent study on the gastrula fate map of the sea anemone Nematostella vectensis challenges our long-standing conceptions on the evolution of cnidarian and bilaterian germ layers and guts. Keywords Cnidaria . Porifera . Placozoa . Ctenophora . Gastrovascular system . Gut evolution . Extracellular digestion . Intracellular digestion . Germ layer evolution Introduction ester bonds. -
The Use of Inflammation by Tumor Cells
223 COMMENTARY The Use of Inflammation by Tumor Cells 1 Jose-Ignacio Arias, M.D., Ph.D. 2 Marı´a-Angeles Aller, M.D., Ph.D. 2 Jaime Arias, M.D., Ph.D. 1 Servicio de Cirugı´a General, Hospital Monte Naranco, Oviedo, Asturias, Spain. 2 Ca´tedra de Cirugı´a, Departamento de Cirugı´a I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain. ancer is malignant, because tumor cells invade neighboring tis- Csues and survive in these ectopic sites. This invasion permits them to enter into the circulation, from which they can reach distant organs and, eventually, form secondary tumors, called metastases.1 The classical metastatic cascade encompasses intravasation by tumor cells, circulation of these cells in lymph and blood vascular systems, arrest in distant organs, extravasation, and growth into met- astatic foci.1,2 However, the tumor cells can adopt a great variety of phenotypes; and, due to this plasticity of the malignant cells; it has been proposed that a more dynamic view is needed for the metastatic cascade.2,3 Invasion and metastases are not unique for cancer, because they also occur during embryonic development, in adult tissue mainte- nance, and in many noncancerous diseases, such as in repair pro- cesses.1,2 In relation to the latter, tumor cells have been described as wounds that do not heal.4 Both tissue repair, a beneficial process, and tumor formation, a harmful process, share some molecular mechanisms that can be ascribed to inflammation.1,2,5 Therefore, in one sense, it is possible that inflammation is shared by both processes: tissue repair and tumor formation. -
Antenatal Diagnosis of Microvillus Inclusion Disease
Obstetrics & Gynecology International Journal Case Report Open Access Antenatal diagnosis of microvillus inclusion disease Abstract Volume 12 Issue 4 - 2021 Microvillus inclusion disease is a rare autosomal recessive disorder due to defective apical Gular Israfilova, Banu Arslanca, Yavuz Emre surface of the enterocytes presenting with severe watery diarrhea starting at birth. We describe a female infant who had antenatal diagnosis of microvillus inclusion disease. At Sukur, Acar Koç Department of Obstetrics and Gynecology, Ankara University 36th gestational week of a 32-year-old woman ultrasound examination revealed dilatation of School of Medicine, Turkey fetal sigmoid colon. The amniotic fluid level was normal. An amniocentesis was performed to rule out congenital sodium and chloride diarrhea in the prenatal period. The patient didn’t Correspondence: Gular Israfilova, MD, Ankara University prefer to undergo genetic tests. In conclusion, prenatal ultrasonographic identification of School of Medicine, Department of Obstetrics and Gynecology, dilated bowel loops without polyhydramnios suggests differential diagnosis of microvillus Dikimevi, Ankara, Turkey, Tel 0090 5375752340, inclusion disease in addition to congenital chloride diarrhea, jejunoileal atresia, volvulus, Email meconium ileus, Hirschsprung disease, enteric duplications, anorectal atresia. Received: July 29, 2021 | Published: August 12, 2021 Keywords: congenital diarrhea, microvillus inclusion disease, prenatal diagnosis Introduction respectively. On postpartum 3rd day, the neonate suffered from watery diarrhea and abdominal distension. Abdominal X-ray showed dilated Microvillus inclusion disease (MVID) is a congenital bowel intestinal loops and pneumoperitoneum (Figure 2). On postpartum 5th disease characterized by severe diarrhea, malabsorption and day, the infant was referred to the gastroenterology department due to 1 growth retardation in infancy. Severe watery diarrhea begins in the 19% weight loss. -
1999, a Cluster of Microvillous Inclusion Disease in the Navajo
A cluster of microvillous inclusion disease in the Navajo population John F. Pohl, MD, Mitchell D. Shub, MD, Eric E. Trevelline, MD, Kristy Ingebo, MD, Gary Silber, MD, ANancy Rayhorn, RN, BSN, Steve Holve, MD, and Diana Hu, MD riod.1 The prognosis is generally poor, We report 4 unrelated patients with characteristic microscopic findings of with most patients dying by the second microvillous inclusion disease (MID) with early-onset phenotype. All 4 pa- decade of life as a result of complica- tients came from the Navajo reservation in northern Arizona. A literature tions of parenteral alimentation includ- 4 search revealed a fifth unrelated Navajo child with MID. The unusually ing liver failure or sepsis. Various high incidence in this population indicates that a founder effect might be re- treatments including glucocorticoids, sponsible for an increased frequency of this rare genetic disorder in the pentagastrin, human epidermal growth factor, disodium cromoglycate, adreno- Navajo. It is recommended that all Navajo infants presenting with severe corticotropic hormone, prednisolone, diarrhea during early infancy undergo investigation for MID. (J Pediatr and elemental formula feedings have 1999;134:103-6) failed.5-7 However, somatostatin, which is not universally successful,8 reduced stool output in 2 patients,9,10 with an increased weight velocity Microvillous inclusion disease, a rare children with a specific subset of in- noted in 1.10 Loperamide has only disorder with an unknown cause, re- tractable diarrhea and described com- transiently decreased stool output.1 sults in an intractable secretory diar- plete villous atrophy, crypt hypoplasia, Three patients have received intestinal rhea that begins in early infancy. -
Digestive Enzymes: the Key to Optimum Health
Education Article Digestive Enzymes: The Key to Optimum Health Digestion is essential for good health. Unlocking nutrients from foods is a complex process. In order to break down food we rely on optimal levels and function of a special set of proteins called digestive enzymes. These proteins are found in the saliva and also in the small intestines. Without the combined actions of our digestive enzymes we would simply be unable to absorb many nutrients that we need to maintain good health. This is why reduced levels of digestive enzymes can be linked to a wide-range of symptoms within the gut and beyond. Digestive enzymes, along with stomach acid, play a crucial role in the initial stages of digestion, i.e. the breaking down of the food that we eat. The main classes of human digestive enzymes include proteases, lipases and carbohydrases, which respectively break down the macronutrients protein, fats and carbohydrates. If we do not efficiently digest these foods then vital nutrients such as essential fats, vitamins, minerals and phytonutrients cannot be absorbed. What is more, undigested or partially digested food passes through into the large intestines and is fermented by the resident colonic bacteria, causing unpleasant symptoms such as bloating and flatulence and contributing to a toxic bowel. Naturopaths believe toxicity within the bowel is the root of all disease. We do not make digestive enzymes for every type of food that we eat, such as gluten and phytic acid found in some grains and cereals and lactose, a sugar found in milk. This means our bodies may find it difficult to digest these types of foods. -
Small Mammal Population Dynamics and Range Shifts with Climate
RESOURCES, DATA RESOLUTION AND SMALL MAMMAL RANGE DYNAMICS Nerissa Haby B. Env. Sci. (Hons) A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy April 2012 Ecology and Evolutionary Biology University of Adelaide, Australia Table of contents Table of contents i Abstract ii Acknowledgements iii Declaration iv How well do existing evaluations of climate change impacts on range Introduction 1 dynamics represent Australian small mammals? Improving performance and transferability of small-mammal species Chapter 1. 8 distribution models Chapter 2. Specialist resources are key to improving small mammal distribution models 22 Scale dependency of metapopulation models used to predict climate change Chapter 3. 35 impacts on small mammals Lessons from the arid zone: using climate variables to predict small mammal Chapter 4. 52 occurrence in hot, dry environments Ecosystem dynamics, evolution and dependency of higher trophic organisms Chapter 5. 69 on resource gradients Conclusion 79 References 89 Appendix 106 Publications associated with this thesis 153 i Abstract Extensive range shift and mass extinctions resulting from climate change are predicted to impact all biodiversity on the basis of species distribution models of wide-spread and data-rich taxa (i.e. vascular plants, terrestrial invertebrates, birds). Cases that both support and contradict these predictions have been observed in empirical and modelling investigations that continue to under-represent small mammal species (Introduction). Given small mammals are primary or higher order consumers and often dispersal limited, incorporating resource gradients that define the fundamental niche may be vital for generating accurate estimates of range shift. This idea was investigated through the influence of coarse to fine resolution, landscape- and quadrat-scale data on the range dynamics of four temperate- and five arid-zone small mammals. -
Diet, Ecology, and Dental Morphology in Terrestrial Mammals – Silvia Pineda-Munoz – November 2015
DIET, ECOLOGY, AND DENTAL MORPHOLOGY IN TERRESTRIAL MAMMALS Sílvia Pineda-Munoz, MSc Department of Biological Sciences Macquarie University Sydney, Australia Principal Supervisor: Dr. John Alroy Co-Supervisor(s): Dr Alistair R. Evans Dr Glenn A. Brock This thesis is submitted for the degree of Doctor of Philosophy April 2016 2 To my Little Bean; and her future siblings and cousins Al meu Fessolet; I als seus futurs germans i cosins i ii STATEMENT OF CANDIDATE I certify that the work in this thesis entitled “Diet, ecology and dental morphology in terrestrial mammals” has not previously been submitted for a degree nor has in been submitted as part or requirements for a degree to any other university or institution other than Macquarie University. I also certify that this thesis is an original piece of research and that has been written by me. Any collaboration, help or assistance has been appropriately acknowledged. No Ethics Committee approval was required. Sílvia Pineda-Munoz, MSc MQID: 42622409 iii iv Diet, ecology, and dental morphology in terrestrial mammals – Silvia Pineda-Munoz – November 2015 ABSTRACT Dietary inferences are a key foundation for paleoecological, ecomorphological and macroevolutionary studies because they inform us about the direct relationships between the components of an ecosystem. Thus, the first part of my thesis involved creating a statistically based diet classification based on a literature compilation of stomach content data for 139 terrestrial mammals. I observed that diet is far more complex than a traditional herbivore-omnivore-carnivore classification, which masks important feeding specializations. To solve this problem I proposed a new classification scheme that emphasizes the primary resource in a given diet (Chapter 3). -
Anatomy of the Digestive System
The Digestive System Anatomy of the Digestive System We need food for cellular utilization: organs of digestive system form essentially a long !nutrients as building blocks for synthesis continuous tube open at both ends !sugars, etc to break down for energy ! alimentary canal (gastrointestinal tract) most food that we eat cannot be directly used by the mouth!pharynx!esophagus!stomach! body small intestine!large intestine !too large and complex to be absorbed attached to this tube are assorted accessory organs and structures that aid in the digestive processes !chemical composition must be modified to be useable by cells salivary glands teeth digestive system functions to altered the chemical and liver physical composition of food so that it can be gall bladder absorbed and used by the body; ie pancreas mesenteries Functions of Digestive System: The GI tract (digestive system) is located mainly in 1. physical and chemical digestion abdominopelvic cavity 2. absorption surrounded by serous membrane = visceral peritoneum 3. collect & eliminate nonuseable components of food this serous membrane is continuous with parietal peritoneum and extends between digestive organs as mesenteries ! hold organs in place, prevent tangling Human Anatomy & Physiology: Digestive System; Ziser Lecture Notes, 2014.4 1 Human Anatomy & Physiology: Digestive System; Ziser Lecture Notes, 2014.4 2 is suspended from rear of soft palate The wall of the alimentary canal consists of 4 layers: blocks nasal passages when swallowing outer serosa: tongue visceral peritoneum, -
All About Food Webs
fact sheet All about food webs We all need energy to live, so do other animals! An animal’s energy is derived from the food it eats. Different animals eat different things as their energy source: carnivores herbivores omnivores only eat animals (meat) only eat plants eat animals and plants Plants produce their own food, using energy from the sun, by a process called water + carbon dioxide + sunlight photosynthesis. Because they make their own food plants food + oxygen are called ‘producers’. Animals are called ‘consumers’, because they get their energy by consuming other things. What do you think these eat? • insectivore • nectarivore • frugivore ast0890 | Feeding relationships 3: All about food webs (fact sheet) developed for the Department of Education WA © The University of Western Australia 2012 for conditions of use see spice.wa.edu.au/usage version 1.1 revised November 2015 page 1 Licensed for NEALS A food chain shows what consumes what in an environment, that is, species that are linked to each other by what they eat. It also illustrates the direction in which energy passes from one species to the next. acacia cicada green tree frog freshwater crocodile Acacia plants are producers. The arrow shows at the beginning of the food chain, cicadas eat acacia, so cicadas are called ‘first order’ consumers. Next in the food chain, green tree frogs eat cicadas, so green tree frogs are ‘second order’ consumers. Then, freshwater crocodiles eat frogs, so freshwater crocodiles are ‘third order’ consumers. Each animal is named a different order of consumer, based on its position in a particular food chain.