Digestive System II Flashcards
how long does the bolus remain in the stomach?
2-4 hours
why does the pyloric sphincter release the chime a little bit at a time?
because chime has a very low pH
length of small duodenum
25 cm
length of jejunum
2.5 m
length of ileum
3.5 m
how does small intestine get its name?
small diameter
how much absorption occurs in the small intestine?
90%
is digestion of macro molecules complete once chime leaves the stomach?
No, continues in small intestine
fingerlike projections of mucosa
Vili
projections of apical membrane of intestinal absorptive cells
Microvilli
the striated border caused by
Microvilli
what are the three things that increase the surface area of the small intestine?
Microvilli
Vili
Plicae circulares
permanent folds that have core of submucosa
Plicae circulares
projections of the small intestine that are 0.5-1.5mm in length
Vili
what is at the core of the Plicae circulares?
submucosa
what is the core of the vili
lamina propria
what is the core of microvilli
actin
absorptive cells of the small intestine
enterocytes
mucosa is made of
epithelium & Crypts of Lieberkühn
what type of gland is the crypt
tubular glands
what types of cells are in Crypts of Lieberkühn
Paneth cells
Enteroendocrine cells
Stem cells
are paneth cells endocrine of exocrine?
exocrine
what do paneth cells secrete?
lysozymes
what is the function os paneth cells
keep bacterial flora of S. intestine in check
what are the properties the secretory granules of paneth cells
large graphics las at apical surface
eosinophilic
what cells can be found in the submucosa of the duodenum ?
Brunner’s glands
what do Brunner’s glands secrete?
produce alkaline mucous
how many layers of smooth muscle does the small intestine have?
2:
Outer longitudinal
Inner circular
what portion(s) of the small intestine are covered by serosa?
jejunum & ileum
what portion(s) of the small intestine are covered by adventitia?
duodenum portions that are retroperitoneal
structures that are covered by serosa are what?
intraperitoneal
structures that are covered by adventitia are what?
retroperitoneal
where do Brunner’s glands secrete
into crypt
what do Brunner’s glands secrete?
Mucin
what does the Brunner’s glands secretion do?
helps to neutralize chime
alkaline
where do the cells of the crypt not go beyond?
muscularis mucosa
what is important for fat absorption
lacteals
lymphatic nodules are more concentrated in what portion of the small intestine?
ileum
what are the collection of lymphatic nodules in the ileum called?
payers patches
what kind of stain affinity do payers patches have?
Basophilic
what do M cells transfer their sampling of intestinal material, from the lumen, to?
Macrophages
what type of nodules are present in the lamina propria and submucosa of the ileum
lymphatic