Gastrointestinal Tract Structure
Start with the big picture
The GI tract includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus. From the esophagus to the anus, its wall is organized into mucosa, submucosa, muscularis externa, and an outer serosa or adventitia. The mucosa includes an epithelial lining, lamina propria, and muscularis mucosae; the submucosa contains connective tissue and Meissner’s plexus, while the muscularis externa includes circular and longitudinal muscle with Auerbach’s plexus. Regional structure supports different functions: the esophagus has stratified squamous epithelium, the stomach has three muscle layers and specialized glands, and the small intestine has absorptive surface specializations. The large intestine lacks villi and has many goblet cells and haustra. Recognizing these patterns helps connect anatomy with GI function.
What you'll learn
- Identify the major segments of the gastrointestinal tract.
- Name the four main layers of the GI wall and key structures within them.
- Distinguish structural features of the esophagus, stomach, and intestinal segments.
- Relate small- and large-intestinal adaptations to their roles.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
