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What is the function of the collagen table in the lamina propria of the large intestine?
What is the function of the collagen table in the lamina propria of the large intestine?
What is the name of the region between the teniae coli that exhibits sacculations in the large intestine?
What is the name of the region between the teniae coli that exhibits sacculations in the large intestine?
What is the name of the small fatty projection on the serosa outer surface of the large intestine?
What is the name of the small fatty projection on the serosa outer surface of the large intestine?
What is the approximate turnover time of mucosal epithelial cells in the large intestine?
What is the approximate turnover time of mucosal epithelial cells in the large intestine?
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What is the name of the lymphatic nodules that are abundant in the large intestine and extend into the sub-mucosa?
What is the name of the lymphatic nodules that are abundant in the large intestine and extend into the sub-mucosa?
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What is the name of the thickened equally spaced parts of the outer longitudinal layer in the muscularis externa of the large intestine?
What is the name of the thickened equally spaced parts of the outer longitudinal layer in the muscularis externa of the large intestine?
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What is the name of the glands present in the mucosa of the large intestine?
What is the name of the glands present in the mucosa of the large intestine?
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What is the region of the large intestine where teniae coli are absent?
What is the region of the large intestine where teniae coli are absent?
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What is the characteristic of the solitary lymphatic follicles in the small intestine?
What is the characteristic of the solitary lymphatic follicles in the small intestine?
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What is the function of the intestinal glands or crypts of Lieberkuhn in the small intestine?
What is the function of the intestinal glands or crypts of Lieberkuhn in the small intestine?
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Which of the following arteries supplies the jejunum and ileum?
Which of the following arteries supplies the jejunum and ileum?
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What is the characteristic of the villi and microvilli in the small intestine?
What is the characteristic of the villi and microvilli in the small intestine?
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What is the function of the duodenal glands or Brunner's glands in the small intestine?
What is the function of the duodenal glands or Brunner's glands in the small intestine?
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What is the characteristic of the nerve supply of the small intestine?
What is the characteristic of the nerve supply of the small intestine?
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What is the location of the myenteric plexus of Auerbach in the small intestine?
What is the location of the myenteric plexus of Auerbach in the small intestine?
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What is the characteristic of the aggregated lymphatic follicles or Peyer's patches in the small intestine?
What is the characteristic of the aggregated lymphatic follicles or Peyer's patches in the small intestine?
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What is the primary function of the Weii Developed Pericryptal Fibroblast Sheath in the large intestine?
What is the primary function of the Weii Developed Pericryptal Fibroblast Sheath in the large intestine?
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Which layer of the large intestine is characterized by the absence of lymphatic vessels?
Which layer of the large intestine is characterized by the absence of lymphatic vessels?
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What is the unique feature of the muscularis externa in the large intestine?
What is the unique feature of the muscularis externa in the large intestine?
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What is the function of the Teniae coli in the large intestine?
What is the function of the Teniae coli in the large intestine?
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What is the characteristic of the mucosa in the rectum?
What is the characteristic of the mucosa in the rectum?
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What is the unique feature of the appendix?
What is the unique feature of the appendix?
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Which layer of the large intestine is absent where the intestine is attached to adjoining structures?
Which layer of the large intestine is absent where the intestine is attached to adjoining structures?
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What is the reason for the delay in the spread of cancers in the large intestine?
What is the reason for the delay in the spread of cancers in the large intestine?
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Study Notes
Large Intestine
- Consists of Cecum, Colon, Rectum, and Anal canal
- Has 4-layer characteristics of the alimentary canal with adaptations and distinctive features based on functional requirements
- Gross anatomy:
- Identified by the presence of teniae coli (3 thickened equally spaced parts of the outer longitudinal layer in the muscularis externa)
- Absent in the rectum, appendix, and anal canal
- Haustra: Sacculations on the external surface of the cecum and colon
- Omenta appendices: Small fatty projections on the serosa outer surface
Histology
- Mucosal layer:
- Made up of Columnar epithelium
- Contains numerous straight tubular intestine glands (crypts of Lieberkuhn)
- Other cell types: enterocytes, Goblet cells, enteroendocrine cells, and M cells
- Plicae, villi, microvilli, and glycocalyx are less prominent compared to small GI
- Lamina propria:
- Special features: Collagen table (regulates absorption of water and electrolytes from ECF to ICF)
- Well-developed GALT (large lymphatic nodules abundant in the large bowel and extends into the sub-mucosa)
- Well-developed Pericryptal Fibroblast Sheath (a group of fibroblasts that divide beneath the glands and migrate towards the lumen)
- Absence of lymphatic vessels (present in the muscularis mucosae)
Sub-mucosal
- Contains secreory glands, vascular capillaries, lymphatic vessels, and nodules
Muscularis Externa
- Made of smooth muscles in 2-layers (inner circular and outer longitudinal)
- The outer longitudinal layer has teniae coli and the saccules (Haustra) that become prominent during colon contractions
- Colon is capable of segmental contraction which does not affect the contents unlike peristalsis
Serosal
- Made of simple squamous epithelium (mesothelium) and a small amount of connective tissue
- Absent where the intestine is attached to adjoining structures
Cecum and Appendix
- Cecum is the blind pouch distal to the ileocecal valves and the appendix is the finger-like projection of the cecum
- Cecum has the same histology as the colon
- Muscularis externa of the appendix has no inner circular layer, only longitudinal which is smooth
- Abundance of lymphatic nodes that extend into the sub-mucosa
Rectum and Anal Canal
- Rectum is the dilated distal portion of the alimentary canal
- Mucosa is like that of the distal colon having straight tubular intestinal glands with many Goblet cells
- The other layers are typical of the colon
- No Teniae coli in the rectum
Characteristics of Small Intestine
- Lymphatic follicles: solitary lymphatic follicles are 1-2 mm in diameter, and aggregated lymphatic follicles or Peyer's patches form circular or oval patches
- Large surface area:
- Great length of the intestine
- Presence of circular folds of mucous membrane
- Villi and microvilli
- Intestinal glands or crypts of Lieberkuhn:
- Simple tubular glands distributed over the entire mucous membrane of the jejunum and ileum
- Secrete digestive enzymes and mucus
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Description
This quiz covers the parts and characteristics of the large intestine, including the cecum, colon, rectum, and anal canal. Learn about the 4-layer characteristics and adaptations of the large intestine.
