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Die morfologie van die maagmukosa van die Suid-Afrikaanse krimpvarkie, Atelerix Frontalis

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dc.contributor.advisor Coetzee HL, Dr en
dc.contributor.advisor Loots GP, Prof en
dc.contributor.author Gregorowski MD en
dc.date.accessioned 2016-09-26T06:26:43Z
dc.date.available 2016-09-26T06:26:43Z
dc.date.submitted 1990 en
dc.identifier.uri http://hdl.handle.net/20.500.11892/173997
dc.description.abstract The aim of this study was the investigation of the histology and ultrastructure of the stomach mucosa of the feeding and fasting South African hedgehog, <i>Atelerix frontalis</i>. The stomach of <i>A. frontalis</i> is situated between the oesophagus and duodenum and displays lesser and greater curvatures. The mucosa, submucosa, <i>muscularis externa</i> and serosa form the stomach wall and both the mucosa and submucosa are involved in the formation of the <i>rugae</i>. The mucosa consists of the surface epithelium, glands, <i>lamina propria </i>and <i>muscularis mucosae</i>. The different cell types and the distribution of these cell types, lead to the dividing of the mucosa into a cardia, fundus and pyloric area. The cardiac and pyloric areas respectively form a narrow band distal to the oesophageal opening and proximal to the pyloric sphincter. The area between these two regions forms the fundus. A single layer of columnar epithelium covers the surface of the stomach and the gastric pits, which indent the surface of the stomach to a varying degree in the different regions of the stomach. The gastric pits penetrate to a depth of one half the thickness of the mucosa in the cardiac and pyloric areas, while the pits of the fundus penetrate to a depth of one fifth or one sixth the thickness of the mucosa. Simple tubular glands open into the bottom of the gastric pits. Cardiac mucous cells line the cardiac glands while the fundic glands are composed of mucous neck cells, parietal cells and chief cells. Cells with prominent dilated rough endoplasmic reticulum are also observed in the fundic glands of these animals. The pyloric glands are formed by mucous-like cells and two different cell types, a "light-" and "dark cell" are present in the basal part of the pyloric glands. Endocrine cells are scattered individually among the other gland cells. Five different endocrine cell types are observed . Cell type I corresponds to the ECL-cells, cell type II to the X-cells, cell type III to the EC-cells, cell type IV to the D-cells, and cell type V to the G-cells of different animal species. The <i>lamina propria</i> is greatly displaced by the glands and consists of collagen and reticular fibres, fibroblasts, mast cells, eosinophils, as well as amorphous ground substance. Blood vessels, unmyelinated nerve fibres and strands of smooth muscle from the <i>muscularis mucosae</i> also form an integral part of the <i>lamina propria</i>. The <i>muscularis mucosae</i> consists of inner circular and outer longitudinal smooth muscle layers. An increased number of apical secretory granules are observed in the cardiac mucous cells, mucous neck cells of the fundic glands and pyloric gland cells of the fasting <i>A. frontalis</i>, as well as dilated granular endoplasmic reticulum cisternae which are characteristic features of the cardiac mucous cells, mucous neck cells of the fundic glands and chief cells. No differences are however visible in the surface epithelium and parietal cells of the fasting <i>A. frontalis</i>. On macroscopic, as well as light and electron microscopic level, the stomach of <i>A. frontalis</i> generally agrees with that of other mammals, especially the European hedgehog, <i>Erinaceus europaeus</i>. The distribution of the acid and neutral mucins in the surface epithelium, mucous neck cells, cardiac mucous cells and pyloric gland cells, constitute the main difference between the cell types of the various species. The presence of acid mucins in the mucous neck cells of <i>A. frontalis</i> differ from the European hedgehog, where neutral mucins are present. Fibrous material, arranged in concentric layers, is present in the parietal cells of <i>A. frontalis</i>. These structures seem to be characteristic of the parietal cells of the family Erinacidae. The function of this structure is unknown. The presence of "light" and "dark cells" in the basal regions of the pyloric glands differ from other mammals, where only one type of exocrine gland cell, usually mucous neck cells, is described. en
dc.language Afrikaans en
dc.subject Zoology en
dc.subject Physiology and anatomy en
dc.title Die morfologie van die maagmukosa van die Suid-Afrikaanse krimpvarkie, Atelerix Frontalis en
dc.type Masters degree en
dc.description.degree MSc en

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