9 22 Digestion of proteins and fats-Table 1 Flashcards
what do parietal cells secrete?
HCL (pH in the stomach); Intrinsic factor
what do chief cells release?
they release pepsinogen.
what is pepsinogen?
it is the inactive part of pepsin, that is activaated in acid environment.
how does pepsin activate?
by cleaving inhibitory peptide and activating in acid
what is the first pepsidase in digestion of protein?
pepsin
what are the three pancreatic enzymes released for the digestion of protein?
procarboxypetidase; chymotrypsinogen;; trypsinogen
how do we activate the pancreatic enzymes
enteropeptidase activates trypsinogen to trypsin. Trypsin activates procarboxypeptidas; and chymotrypsonogen, and itself (trypsinogen)
the three activated pancreatic enzymes that go on to digest proteins as they enter the small intestine:
carboxypeptidase; chymotrypsin; trypsin
Brief overview of the protien digestion:
protein in the stomach: (combine B12 and Intrinsic factor.) Pepsinogen is activated to pepsin and start to digest the proteins. then IF/B12 and protein out the stomach, HCO3 buffer, and then activated carboxypeptidase, chymmotrypsin, and trypsin digest the protein in the small intestine down to amino acids.
where is enteropeptidase?
in the intestinal microvilli
what are the Enzymes that are activated by Trypsin?
Trypsinogen; Proelastase; Procarboxypeptidase; chymotrypsinogen; procolipase
what is procolipase
the inactive form of colipase that is required for activity of lipase that breaks down fats
what is proelastase
protease that breaks down elastic fibers
what will digest a lipid from a triacylglycerols to individual lipid chains?
pancreatic lipase
briefly describe the absorbtion of proteins into the blood stream
active transport by Na co-transporter into the absorptive cell, transcytosis, facilitated diffusion and then enter capillary via intercellular clefts
What are the brush border protiens?
Enteropeptidase; disaccharidases; peptidases;
how can block in the pancreatic duct cause pancreatitis?
The proteases of the pancreus can be activated by trypsin and start to break down the proteins fo the pancreus.
why would a proton pump inhibitor lead to vitamin B12 deficiency?
perhaps this messes with the parietal cells and the pressence of the intrinsic factor for B12.
what is a bile salt
emulsification (like a detergent) to break up the lipids
explain the digestion of lipids:
go to the stomach, and then into the small intestine, and the gall bladder dumps in bile salts, emulsification of lipids, procolipase activated by trypsin and becomes colipase that combines with lipase and digest the fat, and micelles get absorbed.
what is the result (for transporting the molecule) of the extreme hydrophobicity of lipids
they do not cross the membranes
what will cut the back bone of the triglycerides to leave three seperate strands?
Pancreatic lipase.
Brief overview of fat digestion
Duodenum: bile salts released from gall bladder and emulsify the fat. lipase and colipase (activated from procolipase by trypsin) break down the lipids, and make little miscelles that get absorbed.
what is the bile salt made from?
cholesterol
what is a micelles
made of fatty acids, monoglycerides, and bile salts. AND FAT SOLUBLE VITAMINS.
how are miclessles absorbed?
absorbed epithelal of small intestine, then absorbed as chylomicrons into the lacteal of the lymphatic system.
the large triacylglycerol-rich lipoprotein particles secreted by the intestinal mucosal cells into the lymph
chylomicrons
briefly describe the structure of the chylomicrons
inner core of tryiacylglycerols, and cholesteryl esters, and fat-soluble vitamins, phospholipid coat, with apoprotein spot and unesterifed cholesterol spots.
how do chylomicrons change the blood plasma
make it dark and cloudy, merky looking.
what is the destination of sugars, amino acids, and fat in the digestive system?
sugars/amino acids go to the blood (through capillary in the villus of the intestine). Fat go to the lymph. (through the lacteal in the villus of the intestine)
what are the fat soluble vitamins?
A,E,D,K
What is an omega 3 fatty acid
the first double bond is at the third carbon form the omega end of the lipid (the omega end is at the end of the long carbon chain.)
know which is an essential fatty acid
Omega-3s
why vitamin E deficient with CF
Vitamin E is fat soluble and CF often attacks the pancreus, therefore we don’t get lipase or colipase, and there are no lipases on the brush border.
introduced gluten, and this flattened the cilia of his small intestine.
Celiac disease!
