absorption and secretion Flashcards
how are amino acids absorbed
sodium dependant co transport in the small intestine
how are dipetides absorbed
H+ dipeptide cotransport
how are tripeptides absorbed
H+ tripeptide cotransport
what is the role of gastric lipase
slow the rate of gastric emptying
hydrolyse triglycerides
what are chylomicrons made of
core of triglycerides and cholesterol ester
phospholipids and apolipoproteins on the outside
where do the chylomicrons go next
packaged into secretory vesicles on the Golgi membrane and exocytosed across the basolateral membrane
then enter the lacteals
describe the tight junctions in the intestine
small intestine- leaky
colon- impermeable so no paracellular route for fluids and electrolytes
what are crypts of Lieberkuhn for
secretion
what are colonic glands for
secretion
where is the zone of cell proliferation
base of the crypts, replaces the villous cells
what is a secretagog
a substance that promotes secretion
describe the absorption of lipids
Bile salts form micelles
Diffusion of products into intestinal cells
Re-esterification within the cell to
triglycerides and cholesterol
Chylomicrons form in the cell and transfer to
lymph
how is bile absorbed
sodium dependant co transport
how is iron absorbed
binds to apoferritin in the intestinal cell and transferrin in the blood
how is calcium absorbed
vitamin D dependant Ca+ binding protein- Calbindin