Introduction
Shayne C. Gad in Toxicology of the Gastrointestinal Tract, 2018
The mucosa contains many deep crevices lined with glandular epithelium. Cells lining the crevices form the intestinal glands (crypts of Lieberkühn) and secrete intestinal juice. Many of the epithelial cells in the mucosa are goblet cells, which secrete mucus. Paneth cells, found in the deepest parts of the intestinal glands, secrete lysozyme, a bactericidal enzyme, and are capable of phagocytosis. They may have a role in regulating the microbial population in the intestines. Three types of enteroendocrine cells, also in the deepest part of the intestinal glands, secrete hormones: secretin (by S cells), cholecystokinin (by CCK cells), and glucose-dependent insulinotropic peptide (by K cells). The lamina propria of the small intestine has an abundance of MALT. Solitary lymphatic nodules are most numerous in the distal part of the ileum. Groups of lymphatic nodules referred to as aggregated lymphatic follicles (Peyer’s patches) are also present in the ileum. The muscularis mucosae consists of smooth muscle. The submucosa of the duodenum contains duodenal (Brunner’s) glands, which secrete an alkaline mucus that helps neutralize gastric acid in the chyme. Sometimes the lymphatic tissue of the lamina propria extends through the muscularis mucosae into the submucosa.
The digestive system
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella in Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
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.
Gastrointestinal Lymphatics
Waldemar L. Olszewski in 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
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.
Bladder neoplasms and NF-κB: an unfathomed association
Published in Expert Review of Molecular Diagnostics, 2020
Charles Emmanuel Jebaraj Walter, Sankari Durairajan, Kalaiselvi Periyandavan, George Priya Doss C, Dicky John Davis G, Hannah Rachel Vasanthi A, Thanka Johnson, Hatem Zayed
Histologically, the bladder wall consists of three layers: mucosa, muscularis propria and adventitia, with the serosa/peritoneum at the dome. The mucosa is subdivided into the urothelium, lamina propria, and discontinuous muscularis mucosa. The bladder urothelium is composed of the epithelium (urothelium) that lines the renal pelvis, ureter, bladder, and most of the urethra, with the exception of the distal urethra. The urothelium can be further categorized as superficial (single layer of umbrella cells protecting the underlying cells from urine exposure), intermediate and basal urothelial cells. The lamina propria is located between the mucosal basement membrane and the muscularis propria composed of loose to dense connective tissue, blood vessels, lymphatic vessels and adipose tissue. The discontinuous muscular mucosa is usually associated with intermediate-sized blood vessels, and only 5% of bladders have a well-developed continuous muscularis mucosa. The muscularis propria consists of inner longitudinal, circular and outer longitudinal layers of thick muscle bundles [16] (Figure 1).
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.
Related Knowledge Centers
- Bladder
- Gastrointestinal Tract
- Mucous Membrane
- Muscle
- Lamina Propria
- Submucosa
- Esophagus
- Urinary System
- Rectum
- Renal Pelvis