7 topics with concise reviews: definitions, key facts, and class questions.
In this section, we examine the microscopic structure of the stomach and small intestine—key regions of the digestive tube where the main stages of chemical processing and nutrient absorption take place.
You will study the cellular composition and histophysiology of gastric glands, comparing the features of the cardiac and pyloric regions. Special attention is paid to the diffuse endocrine system regulating secretion. The block dedicated to the small intestine details the structure of villi, crypts, and all epithelial cell populations. You will learn the structure of the duodenum and the protective role of Paneth cells.
During practical classes and exams, instructors most frequently ask to distinguish fundic glands from pyloric glands, name the functions of parietal and chief cells, and identify Paneth cells under a microscope. Understanding these structures is a classic foundation essential for further studies in physiology and gastroenterology.
How many layers does the muscular coat of the stomach have?
Unlike most parts of the GI tract, the muscular coat of the stomach has three layers: inner (oblique/longitudinal), middle (circular), and outer (longitudinal).
Where are gastric stem cells located?
Undifferentiated (stem) cells are located in the neck of the glands. They provide both rapid renewal of the surface epithelium of the gastric pits (upward) and slow renewal of the gland cells themselves (downward).
How do open enteroendocrinocytes differ from closed ones?
Open enteroendocrinocytes contact the lumen of the gland with their apical pole and respond to the chemical composition of food. Closed ones do not reach the lumen and are regulated solely via neural or humoral signals.
How does the esophageal epithelium differ from the gastric epithelium at the transition zone?
In the cardiac zone, an abrupt change in the lining occurs: the stratified squamous non-keratinized epithelium of the esophagus borders the simple columnar glandular epithelium of the stomach.
Why are smooth myocytes inside the villi needed?
Smooth myocytes derived from the muscularis mucosae provide a pumping function. They contract rhythmically, pushing substances absorbed into the villus vessels further along the bloodstream.
Where are membrane digestion enzymes located?
They are fixed in the glycocalyx layer that covers the microvilli on the apical surface of columnar cells.
Master the entire topic in the "Histology" course
This is a summary. The course covers everything tested in classes and exams.
3,485 pages of study guides for all topics
Assignments and quizzes after every topic — just like in a colloquium