Lecture 22: The Small Intestine Flashcards
What are the 3 main regions of the small intestine?
- Duodenum
- Jejunum
- Ileum
What is the total length of the small intestine?
6m
Where is the initial segment of the duodenum?
Retroperitoneal
What is the small intestine held in place by?
The Mesentery
What does the Mesentery allow?
Allows movement but prevents the SI from getting tangled
What does the Mesentery contain?
4
- Arteries
- Veins
- Nerves
- Lymphatics
What is a property of the chyme received by the SI?
Acidic
What protects the epithelium in the SI?
2
- Mucous secreting cells
- Glands in the submucosa
What is the only section of the SI to contain glands in its submucosa?
Duodenum
What neutralises the acidic chyme in the SI?
Bicarbonate
Where is bicarbonate produced to neutralise chyme?
Pancreas
What are Plicae Circulares (Circular folds)?
Permanent large folds of the small intestine
What is the core of the Place Circulares made of?
Submucosa with overlying mucosa
What is found on the Plicae circulares?
Numerous villi
What does the Muscularis mucosae allow the villi to do?
Allow them to wiggle back and forth
What is the core of the Villi made from?
Fibrous Connective Tissue (lamina propria)
What do the Villi contain?
2
- Lymph lacteal
- Capillary network
What does the lymph lacteal drain?
Products of fat digestion
What does the capillary network drain?
Products of protein and carbohydrate digestion
What does nutrient rich deoxygenated blood in the small intestine enter?
The mesenteric veins
What do the mesenteric veins drain into?
Hepatic portal vein
What pathway do lymph lacteals ultimately drain into?
Into the Cisterna Chyli, thoracic duct and then left subclavian vein
What do mesentery do?
Connect organ to body wall
What is the epithelium of the SI?
Simple columnar
