Lipid Digestion Flashcards
Because lipids are hydrophobic, how are they typically stored in the body?
Compartmentalized
Lipids are hydrophobic or hydrophilic?
Hydrophobic
What are the two major functions of lipids?
energy
hydrophobic barrier
what are the two minor functions of lipids?
co enzyme qualities
homeostasis
what is the function of acid lipases?
target TAG containing short and medium fatty acid chains
what are the two specific types of acid lipases?
lingual
Gastric
what two mechanical actions emulsify dietary lipids?
mechanical action
bile salts
what does pancreatic lipase do?
cleaves fatty acids at carbons 1 and 3
what are the 2 products of pancreatic lipase?
2-monoacylglycerol
free fatty acid
what does colipase do?
binds to pancreatic lipase (1:1)
anchors the pancreatic lipase and promotes its activity w/ bile salts present
what are the 2 forms of dietary cholesterol?
esterfied and nonesterfied (free)
what pancreatic enzyme breaks down esterified cholesterol?
cholesterol esterase
what are the products of cholesterol esterase?
non-esterified cholesterol and free fatty acids
what are the two enzymes that digest phospholipids?
phospholipase A2
lysophospholipase
what are the products of phospholipase A2?
free fatty acid
lysophospholipid
what are the products of lysophospholipidase?
fatty acid
glycerylphosphoryl base
where is CCK released from?
mucosa cells of the duodenum and jejunum
what are 3 effects CCK has on the gastrointestinal system?
bile release from the gallbladder
hydrolytic enzyme release from the pancreas
slows down gastric motility
what does secretin do?
promotes the release of bicarbonate from the liver and pancreas to the small intestine to create the optimal pH in the small intestines for pancreatic enzyme function
lipid digestion in the jejunum generates what?
free fatty acids
free cholesterol
2-monoacylglycerol
how are micelles arranged?
hydrophilic outside
hydrophobic inside
once lipids are absorbed into the entercytes, where are they processed?
ER
what happens to long chain fatty acids in the enterocytes?
converted to active form by fatty-Acyl-Coa synthetase
what happens to 2-monoacylglycerol in the enterocyte?
it is converted into TAG by TAG synthase
what happens to lysophospholipids in enterocytes?
they are reacylated by acyltransferases to form phospholipids
what happens to cholesterol in the enterocyte?
it is esterified
what makes up a chylomicron?
CENTER: TAG + cholesteryl ester
OUTSIDE: phospholipids, cholesterol, Apolipoprotein B-48
what is lymph that contain chylomicrons called?
chyle
what is the route that chyle takes?
lymphatic system to thoracic duct to left subclavian vein to blood
what does lipoprotein lipase do?
degrades TAG in the chylomicrons to free fatty acids and glycerol
what is the free fatty acid that is released from the chylomicron used for?
taken up by muscle and adipose tissue
what is the glycerol used for that is released from chylomicrons?
taken up by the liver for glycolysis or gluconeogenesis
how does cystic fibrosis affect the pancreas?
the defective Cl- pump causes a thick mucus to build up in the secretory pumps of the pancreas
this blocks the excretion of pancreatic enzymes
