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An Investigation in Vitro of the Properties of the Individual Muscle Layers of the Rabbit Colon in an Induced Colitis.
Published in William J. Snape, Stephen M. Collins, Effects of Immune Cells and Inflammation on Smooth Muscle and Enteric Nerves, 2020
WH Percy, MB Burton, Y Jacobowitz, R Burakoff
The muscularis mucosae is important for colonic function because it causes the mucosa to move and thus controls the luminal surface area. Based on the data obtained in the present study, alterations in muscularis mucosae function may be an important first stage in the pathophysiology of inflammatory bowel disease.
Gastrointestinal Lymphatics
Published in Waldemar L. Olszewski, Lymph Stasis: Pathophysiology, Diagnosis and Treatment, 2019
The lymphatic anatomy of the rat stomach was recently investigated with in vivo microscopy following microinjection of a fluorescein-albumin conjugate.16 Mucosal initial lymphatics were found to be confined to the deeper regions, close to the muscularis mucosae. A network of submucosal vessels was also demonstrated in relation to the muscularis mucosae. These mucosal and submucosal networks drain by larger vessels through the deep submucosa and muscularis externa to extragastric vessels on the lesser and greater curvatures. As in earlier studies in the human stomach,17 no lymphatic vessels were observed in the muscularis externa. Other studies in humans18,19 have confirmed the existence of mucosal lymphatics in the deep mucosa close to the muscularis mucosae, but the upper two thirds of the mucosa is normally devoid of lymphatics. In severe atrophic gastritis, however, where the mucosal layer is considerably thinner, initial lymphatics are seen close to the surface epithelium.20 The deep location of initial lymphatics of the human gastric mucosa is similar to that observed in the colon.21
The digestive system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
The innermost layer of the digestive tract wall, the mucosa, is composed of three layers: the mucous membrane, the lamina propria, and the muscularis mucosa. The mucus membrane provides important protective, absorptive, and secretory functions for the digestive tract. The nature of the epithelial cells lining the tract varies from one region to the next. The average life span of these epithelial cells is only a few days, so rapidly dividing stem cells continually produce new cells to replace worn-out epithelial cells. Mucus-secreting goblet cells are found in the mucosa throughout much of the gastrointestinal tract. The lamina propria is a thin, middle layer of connective tissue that contains the capillaries and small lymphatic vessels positioned to collect digested nutrient molecules. It also contains numerous lymph nodules that provide protection against infectious agents. The outer muscularis mucosa is a thin layer of smooth muscle. Contraction of this muscle may alter the effective surface area for absorption in the lumen.
Current status and advances in esophageal drug delivery technology: influence of physiological, pathophysiological and pharmaceutical factors
Published in Drug Delivery, 2023
Ai Wei Lim, Nicholas J. Talley, Marjorie M. Walker, Gert Storm, Susan Hua
The average thickness of the esophageal wall is approximately 1.87 to 2.70 mm in the dilated state and 4.05 to 5.68 mm in the contracted state (Xia et al., 2009). The thickness of the esophageal wall has also been reported to be slightly larger in males (5.26 mm) compared to females (4.34 mm) (Xia et al., 2009). The wall of the esophagus is comprised of the mucosa, submucosa, and muscularis propria (Figure 1). In healthy individuals, the mucosa is composed of three layers – non-keratinized, stratified squamous epithelium; lamina propria (composed of connective tissue); and muscularis mucosa (Scott-Brown et al., 2008; Orlando, 2010; Standring, 2020). The muscularis mucosa is composed primarily of smooth muscle, with a combination of striated muscles at the upper part of the esophagus. The submucosa layer consists of predominantly blood vessels, lymphatic vessels, minor salivary glands, connective tissues, and autonomic nerve plexus (i.e. submucosal plexus). The muscularis propria is formed by a mixture of striated and smooth muscles and is responsible for motor functions of the esophagus.
Factors associated with non-lifting of colorectal mucosal lesions
Published in Scandinavian Journal of Gastroenterology, 2023
Jiang-Ping Yu, Shao-Peng Yang, Rong-Wei Ruan, Sheng-Sen Chen, Yan-Dong Li, Hai-Bin Lou, Shi Wang
To further investigate factors affecting the non-lifting sign, we analyzed the pathological features of 29 non-lifting lesions. As shown in Table 3, only four cases had submucosal invasion, in which most three cases were SM2 and one case was SM3. Sixteen non-lifting lesions had submucosal fibrosis based on intraoperative findings and H&E staining (Figure 2). During dissection of the submucosa, we observed that muscle fibers from the deeper layers extended into the submucosa (Figure 3(a)). Desmin as a smooth muscle cells marker was evenly expressed throughout myofibers. Muscle fibers from the muscularis propria extend into the submucosa and muscularis mucosae as shown in immunohistochemical staining result (Figure 3). Histologic examination showed that there were 9 lesions of MMPA.
Growth of Intestinal Neomucosa on Pedicled Gastric Wall Flap, a Novel Technique in an Animal Model
Published in Journal of Investigative Surgery, 2022
Panagiotis Sakarellos, Apostolos Papalois, Harikleia Gakiopoulou, Iro Zacharioudaki, Michalis Katsimpoulas, Marina Belia, Dimitrios Moris, Kyveli Aggelou, Ilias Vagios, Spiridon Davakis, Michail Vailas, Theodoros Liakakos, Theodoros Diamantis, Evangelos Felekouras, Michael Kontos
The duration of the experiment until sacrifice as well as the size of the laboratory animals appear to correlate with the percentage and the maturity of neomucosa coverage in the literature. The experience gained through this experiment support exactly the above view; the longer the animals survive, the more surface of GWF is covered by neomucosa and the greater the maturity of it. Binnington et al declare that in large animals, extensive intestinal defects require patching, of which coverage needs up to 40 weeks [43, 44]. Additional time is required for the maturation of the other layers of the new intestine as well. Thomson et al recognized as muscularis mucosae a distinct layer of smooth muscle with fibrous components between colon serosa and neomucosa at 8-week period in rabbits [31]. The type of the experimental animal, the duration of the experiment, the type of patch as well as other unknown factors may be related to the fact that we did not recognize muscularis mucosae.