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Chapter 27: Absorption and digestion of Lipids and minerals - Coggle…
Chapter 27: Absorption and digestion of Lipids and minerals
Fat digestion
lingual liase from Ebners gland
mostly begins in deodenum, pancreatic lipase
Colipase - activated by trypsin
cholesterol esterase
bile salts - lecithin
micelles formation
fat Absorption
passive defusion
if <10-12 carbon atoms - pass to blood free
if >10-12 carbon atoms- to insoluble and needs michelle
p458
formation of chylomicron
free FA convert to TG and coated with apoproteins
short chian fatty acids in colon
trophic effect on colonic epithelial cells
combat inflammation
weak acids and good buffer
promote absorption of Na+
vitamins
absorbed in upper small intestine but B12 in ileum
Vitb12 and folate- Na+ dependent
calcium
dependent on Vit D
inh by phosphates and oxalates- insoluble salts with Ca in intestine
iron
20mg needed dly
factors for absorption
phytic acid in cereal decrease absorption
reactos to iron -insol compound
diet- ferric (Fe3+), but only ferrous (Fe2+) absorbed
needs Fe3+ reductase in brush border
DMT1 transporter into enterocytes, transport out ferroportin1. Hephaestin (Hp) associated with ferroportin
needs gastric acid
happens in duodenum
plasma bound to transferrin- converted to Fe3+
Heme binds to apical transport protein in enterocyte
hemosiderin
steatorrhoea
lipase deficiency
lack of alkaline
lowering intestinal pH
pancreatic damage
hypersecretion of gastric acid
defective reabsorption of bile salts in distal ileum
Mg absorption facilitated by protein