Digestion & Absorption I & II Flashcards Preview

Medical Biochemistry > Digestion & Absorption I & II > Flashcards

Flashcards in Digestion & Absorption I & II Deck (25):

In addition to providing amino acids, what other function does proteins serve?

delivers the dietary essential amino acids which cannot be synthesized in humans


What does linoleic acid produce?

arachidonic acid


what does alpha linoleic acid produce?



What is the intrinsic factor formed in the parietal cells of the stomach needed for?

uptake of B12 into the mucosal cells


what is released by parietal cells?

gastric acid (HCL)
G cells release gastrin which releases gastric acid by parietal cells


what do chief cells release?

pepsinogen and gastric lipase


primary bile acids - where are they formed

only formed in liver - the liver uses free cholesterol


secondary bile acid - where are they formed

from primary bile acids and by intestinal bacteria


where are primary and secondary bile acids conjugated?

ONLY in the liver


what does the liver release into bile?

conjugated bile salts, phosphatidylcholine, free cholesterol and conjugated bilirubin


what role does albumin play? (2)

needed for osmolatity and used in blood to transport protein


what do individuals with gout have?

have high uric acid levels in blood


what should individuals with gout eat?

diet low in purine bases


how do fat soluble vitamins (ADEK) and dietary essential fatty acids reach the liver?

chylomicron remnants


how do medium chain FA reach the liver?

released from intestinal mucosal cells directly as
free fatty acids into the portal vein and reach the liver.


what nutrient is rich in medium chain FA?

Medium-chain fatty acids are found in TAGs of milk and this food source allows the rapid uptake into the liver for energy metabolism.

Also, TAGs with medium-chain fatty acids can be degraded by lingual and gastric lipase which do not need bile salts for activity.


why are conjugated bile salts important?

Bile salts are needed for lipid digestion for the action of pancreatic lipase and of pancreatic phospholipase A2.

Last but not least, bile salts are also needed for the uptake of the digested lipids into intestinal mucosal cells.


what do gastic lipase and lingual lipase work on at low pH?

Lingual lipase and gastric lipase act mainly on TAGs with medium-chain fatty acids, as found in milk.


what is an endopeptidase? (like pepsin)

which means that it cleaves proteins from the inside and leads to smaller proteins and peptides.


What does secretin do? (2 things)

Secretin leads to the release of bicarbonate and water from the pancreas.

It also inhibits to a certain degree the release of chyme from the stomach which allows time for neutralization of the present chyme so that the food can be further digested by pancreatic enzymes which need a more neutral pH.


what are CCK main functions?

CCK inhibits gastric motility and production of gastric acid.

CCK also leads to the release of pancreatic enzymes and activation of enteropeptidase which can activate released trypsinogen, but only in the lumen of the duodenum. Water is also released by the pancreas.


what are the specific injury markers of pancreatitis?

pancreatic α-amylase and
pancreatic lipase in the blood.

Often this is due to ethanol abuse, gallstones or very
high levels of VLDL in the blood (hypertriacylglyerolemia). It is also found in
patients with cystic fibrosis


What does pancreatic lipase need to cleave TAGs?

colipase and bile salts


what are the four amino acid inactive proteases in pancreas?

trypsinogen, chymotrypsinogen, proelastase, and two procarboxypeptidases


name the two fat proteases from pancreas?

procolipase and prophospholipase A2