Gastrointestinal system 3 Flashcards
What are the three regions of the small intestine
Duodenum (25cm)
Jejunum (2.5m)
Ileum (3.6m)
What holds the small intestine in place
Initial segment of duodenum - retroperitoneal
Mesentery - Allows movement but prevents tangling
What vessels are in the mesentery
Arteries
Veins
Nerves
Lymphatics
Where are the mucous secreting glands
In submucosa - specifically the duodenum
What are plicae circulares
(Circular folds)
Permanent large folds - submucosal core with overlying mucosa
What allows villi to move back and forth
Muscularis mucosae
villi on surface of plicae circulares
What are villi made up of
Coe of FCT (lamina propria)
Contains: Lymph lacteal (fat digestion and Capilary network (protein and carbohydrate digestion)
Where does deoxygenated blood absorbed in the SI go
Enters mesenteric veins
Drains into hepatic portal vein
Lymph lacteals altimately drain into cisterna chyli, thoracic duct then left subclavian vein
What is another way to increase surface area
Microvilli on apical surface of simple columnar epithelium - microvilli brush boarder
What are Gycocalyx
Glycoproteins - branched filaments - tether enzymes
What is contact digestion
Involves enzymes attached to brush boarder
What is the main junction between epithelial cells
Tight junction (small molecules can diffuse through) - paracellular
What cells are in the Small Intestine and what do they do
Enterocytes - absorptive Goblet - mucous Stem Paneth - antibacterial enzymes Endocrine - hormones
