week 21 lower GI anatomy Flashcards
where does the small intestine run to and from
runs from pyloric sphincter of the stomach to the caecum of the large intestine
how long is the small intestine
6-7 metres long
what are the three regions of the small intestine
duodenum
jejenum
ileum
what is the smallest section of the small intestine
duodenum
the duodenum is continuous with what
stomach
the ileum is continuous with what organ
large intestine
where does the duodenum receive chyme from
stomach via pyloric sphincter
what 4 substances does the duodenum receive from the pancreas
sodium bicarbonate
amylase
lipase
precursors of proteolytic enzymes
what does the duodenum receive from the gall bladder
bile acids
in what part of the small intestine has the most absorptive properties
duodenum
what 3 (elements) does the duodenum absorb
calcium
iron
folate
in what part of the small intestine has the greatest absorptive property for bile acid
ileum
what is the only place in the small intestine that absorbs cobalamin
ileum
the jejunum specialises in the absorption of what
fat
protein
carbohydrates
what is the epithelial structure of the jejunum
simple columnar epithelium
what does the ileum specialise in absorption of
B12 and bile acid
the basic simple columnar epithelial layers are the same as other sites in the GI tract but there are additional modifications in the small intestine to maximise what
surface area
what are plicae circulares
circular folds of the mucosa and submucosa
what are plicae circulares most prominent
distal duodenum and jejunum
the number of plicae circulares decrease in size and number as…
you move along the intestine
when are there no more plicae circulares
proximal area of the ileum
what are villi
finer like projections of epithelium covered lamina propria which protrude into the lumen of the small intestine
what are the functions of the microvilli
projections of the apical surface of the epithelial cells which further increase surface area
how much do micro villi increase absorption
20-30 x