Alimentary system Flashcards
What are the layers of the GI tract walls?
- Mocosa
- Submucosa
- Muscularis propria
- Adventitia
What are the layers of the GI tract mucosa?
- Epithelium
- Lamina propria
- Muscularis mucosae
What is the submucosa?
Layer of supporting tissue containing:
- Blood vessels
- Nerves
- Lymphatics
What are the layers of the muscularis propria?
- Circular smooth muscle layer (inner)
- Longitudinal smooth muscle layer (outer)
What is the adventitia?
Layer of supporting tissue containing:
- Blood vessels
- Nerves
It is called the serosa in the abdomen
What type of epithelia line the oesophagus?
Stratified squamous epithelium (sometimes keratinised)
What types of glands are found in the stomach?
- Oxyntic glands (body + fundus)
- Cardiac glands (cardia)
- Pyloric glands (pylorus)
What types of glands are found in the stomach?
- Cardiac glands: Found in cardia and secretes mucous but does not contain acid-secreting cells.
- Oxyntic glands: Found in the fundus and body of the stomach and contain:
1. Parietal cells
2. Chief cells
3. Mucous-secreting cells
4. Endocrine cells - Pyloric glands: Found in the antrum of the stomach and conain:
1. Mucous-secreting cells
2. G-cells
What are the differences between gastric glands and cardiac/pyloric glands?
- Gastric glands contain parietal (oxyntic) cells and peptic (chief) cells, as well as mucous secreting cells.
- Cardiac/pyloric gands contain mostly mucous secreting cells.
What are the cells found in gastric glands?
- Mucous-secreting cells
- Parietal cells
- Peptic cells
What are the shapes of cells in the gastric glands?
- Mucous-secreting cells: Columnar
- Parietal cells: Central nucleus, ‘fried egg’ shaped
- Peptic cells: Basophilic cytoplasm, basally located nuclei
What are the different types of mucous-secreting cells?
- Surface mucous cells
- Neck mucous cells
What is the function of parietal cells?
Secretes:
- HCl
- Intrinsic factor
What is the function of peptic cells?
Secretes pepsinogens
What is special about the duodenum?
It contains Brunner’s glands
What is the function of Brunner’s glands?
Secretes alkali mucous
What is the structure of the small intestinal epithelium?
The epithelium is made up of villi (peaks) and crypts of Leiberkuhn (clefts)
What type of epithelia is found in the small intestinal lumen?
Simple columnar epithelium (with goblet cells)
What types of cells are found in the crypts of Keiberkuhn?
- Enterocytes
- Stem cells
- Enteroendocrine cells
- Paneth cells
What are the contents of the villous cores if the small intestines?
- Connective tissue
- Blood vessels
- Lymphatic vessels
- Immune cells
- Smooth muscle (from muscularis mucosae)
What are the functions of the myenteric plexus?
Controls intestinal motility
What are the functions of the submucosal plexus?
- Controls absorption
- Controls secretion
- Controls activity of muscularis mucosae
