Small Intestine secretions and GI motility Flashcards
What are the 3 surface area adaptations for the small intestine?
Plicae circularis -> villi -> microvilli
Where are the microvilli found?
On top of intestinal enterocytes
What are the different cell types and their roles?
Enterocytes - absorptive
Goblet cells - secretory
Paneth cells - defense
Enteroendocrine cells - hormone secretion
What are the glands at the bottom of the villi called?
Crypts of Lieberkuhn
What secretes mucous in the small intestine?
Brunner’s glands and goblet cells
How much does the small intestine approx. absorb?
8500mls
What hormones do the enteroendocrine cells produce?
CCK, secretin and motilin
What is the greatest volume of small intestine secretion?
Cl- rich isotonic fluid by crypts
What is the specialization found in the duodenum?
presence of Brunner’s glands in submucosa
Secretes bicarbonate rich secretions - change pH
What is the specialization found in the jejunum?
Plicae circularis - most abundant here
What is the specialization found in the ileum?
Peyer’s patches
What is the main blood supply for the small intestine?
Superior mesenteric artery
What facilitates absorption?
Extensive mucosal vascularization
What are the three types of small intestinal musculature?
Basal tone, mixing contractions and moving contractions
What are segmentation contractions?
Static contractions on either side of the tube
Rhythmic irregular contractions
Divide up luminal content - mixing the chyme
Most common after feeding
