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Learning Objectives
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Identify the organs of the alimentary canal from proximal to distal
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Identify the accessory digestive organs
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20.1: Overview
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This page explains the digestive system's primary role in breaking down food and absorbing nutrients, with the small intestine being the key site for these processes. It categorizes digestive organs into the alimentary canal and accessory organs, highlighting that, although termed "accessory," these organs are vital for efficient digestion and nutrient absorption.
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20.2: Alimentary Canal Organs
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This page discusses the alimentary canal, a 7.62-meter-long tube essential for digestion, detailing its processing of food from mouth to anus through organs like the pharynx, esophagus, stomach, and intestines. It highlights accessory organs such as teeth, tongue, and salivary glands that aid digestion, as well as the canal's four basic tissue layers—mucosa, submucosa, muscularis, and serosa—vital for function and nutrient absorption.
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20.3: Stomach
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This page outlines the stomach's anatomy, describing its four main regions: the cardia, fundus, body, and pylorus, as well as their functions. It highlights the role of the pyloric sphincter in regulating emptying into the duodenum and details the stomach wall's structure, including the unique inner oblique muscle layer. Additionally, it explains the mucosa's gastric pits and glands that produce gastric juice, which contains hydrochloric acid and enzymes essential for digestion.
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20.4: Small Intestine
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This page describes the anatomy and structure of the small intestine, detailing its three regions: duodenum, jejunum, and ileum. It highlights the four-layered wall of the small intestine and emphasizes the specialized mucosal and submucosal features, such as circular folds, villi, and microvilli, which significantly increase absorptive surface area, primarily in the proximal two-thirds, where absorption is most extensive.
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20.5: Large Intestine
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This page describes the anatomy and histology of the large intestine, which includes the cecum, colon, and rectum. Although shorter than the small intestine, it has a larger diameter. It features teniae coli, haustra, and epiploic appendages. The mucosa is made up of simple columnar epithelium with enterocytes and many goblet cells for mucus secretion, aiding in fecal movement and the absorption of water, salts, and vitamins produced by intestinal bacteria.
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20.6: Exercises
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This page provides exercises for labeling anatomical and histological structures of the digestive system, including hollow organs, the oral cavity, teeth, salivary glands, stomach, liver, bile and pancreatic pathways, colon, rectum, and liver histology. It highlights the complexity and organization of the digestive system through a structured identification process for various components.
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20.7: MODELS- Hollow Organs, Teeth, Live/Gall Bladder, Upright Torsos, Mid-Sagittal Head
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This page details the anatomy and histology of the digestive system, covering structures like the oral cavity, stomach, intestines, pancreas, liver, and salivary glands. It discusses various tissue layers, histological features of organs, and includes a dental formula, as well as the organization of salivary glands and the peritoneal cavity.