Anatomy of Small Bowel Flashcards
Where does the duodenum begin?
Pyloric sphincter
What does the duodenum receive and from what?
Chyme
From stomach
What neutralizes the acidic chyme going into the duodenum?
Alkaline mucous released by Brunner’s gland in the sub-mucosa
Pancreatic secretions?
Digestive enzymes from acinar cells
-Alkaline fluid to neutralize
What do bile salts do?
Break down large lipids for attack by TAG lipases
Where are the jejunum and ileum in the peritoneum?
Intraperitoneal
What vertebrae does the jejunum begin at?
L2
What/where are Peyer’s patches?
Ileum
Aggregates of lymphoid tissue
Way to remember order of gut organs?
DJ Ileum
What increases SA of small bowel?
Large circular folds of the villi wall
Villi
Microvilli
Lipid absorption in the small bowel. Sequence of events?
- Ingested lipids are broken down by gastric enzymes & dd secretions (increasing SA)
- Form emulsion droplets
- CCK initiates release of TAG lipases (which hydrolyses the TAG)
- Small chain fatty acids will move into capillaries (diffusion)
- Large chain FA incorporated into chylomicrons
- These are released into lymph vessels by exocytosis
What is water balance driven by?
Solutes (primarily sodium)
Fat soluble vitamins?
Vit A, D, E, K
Water soluble vitamins?
Vit B, C, H
What is segmentation?
Occurs after meals, alternating contraction and relaxation of segments of circular muscle. Initiated by intestinal pacemaker cells
