Small Intestine Absorption Flashcards
Function of plicae in small intestine
slow food movement through
Carbohydrates need to be in this form to enter enterocyte
monosaccharides
How to protect brush border hydrolases in small intestine
heavily glycocylated
protect from proteases
Lactose intolerance pathophys
bacteria in large intestine ferment lactose
⇒ gas + lactic acid
⇒ water enters lumen → diarrhea
SGLT1 function
glucose and galactose transporter
secondary active transport
in enterocytes
GLUT5 function
fructose transporter
facilitated transport
in enterocytes
Trypsinogen
from where
activated how
trypinogen
pancreas
activated via enteropeptidase
Protease secreted by liver
trypsinogen
activated by enteropeptidase
endopeptidase
Where are proteins broken down to single aa
brush border enzymes
Proteases
pepsin
trypsin
brush border enzymes
AA absorbed how
secondary active transport via Na+
PEPT1
cotransport peptides (small chains of aa) w/ H+
cytosolic digestion
aa at basolateral surface
3 basic ways of absorbing protein
single aa via 2˚ active transport
peptides via H+ cotransporter
endocytic abosorption (infants, passive immunity)
Hartnup disease
Phe transporter deficiency
can still be transporterd via linked with other aa
PEPT1 used for
Phe
and cephalosporin/other drugs transport
GLUT 2
moves glucose across basolateral surface
Lipid enzymes
salivary lipase
gastric lipase (important in infants and persons with pancreatic insufficiency)
FA reach duodenum
next
release of CCK
⇒ activate pancreatic acinar secretion of lipase and procolipase
Function of colipase
essential for keeping lipase active when bile is present
bile inactivates pancreatic lipase
Activator of procolipase
trypin
procolipase → colipase
Cholesterol esterase
mechanism
hydrolyze 2 position of cholesterol
Phospholipase A2
phospholipids → FA + lysophospholipids
Orlistat
mechanism
pancreatic lipase inhibitor
weight loss
Basic bile mechanism
one hydrophobic and one hydrophilic end
