digestion and absorption Flashcards
What enzyme is mainly seen in the Jejunum?
pancreactic enzymes
what are the 4 enzymes found in the pancreas?
pancreatic alpha amylase, protease, nuclease & phosphodiesterase
What does pancreatic alpha amylase do?
pancreatic alpha amylase starts in the jejunum and acts on oligosaccharides to form disaccharides( maltose-2 glucose molecules, lactose-galactose and glucose, isomaltose, sucrose-fructose and glucose, this are absorbed in the illeum whic is the last part of reabsorption
what is protease?
an enzyme that cleaves proteins
what is nuclease and phosphodiesterase function?
They digest RNA and DNA to mononucleotides, which are taken up into te mucosal cell
Where is alpha amylase and lingual lipase found?
enzymes found in the mouth
why is lingual lipase important?
it is important because of milk digestion in infants
what does salivary amylase do?
cleaves the alpha 1:4 glycosidic bonds of starch and glycogen and denatures in the stomach so carbohydrate stops before it reaches the stomach where it is a acidic enviornment
what is pancreatitis?
inflammation of the pancreas
what cause pancreatitis?
active trysin in the pancreas or duct where it is not suppose to be,ETHANOL ABUSE( most common), blockage of duct(gallstones, tumor), HYPERTRIACYLGLYCEROLEMIA(elevated lipoproteins with % of TAGS)
what does ethanol abuse cause?
pancreatitis
elevation of lipoproteins with a % of TAGS causes what?
Hypertriacylglycerolemia-pancreatitis
why is pancreatic lipase importatn when it it elevated in the blood stream?
its is an injury marker for the pancreas—> pancreatitis (serum lipase/ alphaamylase 2)
what happens at the cellular level with cycstic fibrosis?
there is a deficiency in the CFTR transporter which causes and increase in mucus which blocks the pancreatic duct
what can cholelithiasis cause?
the cholesterol gallstone disease- which can result from reduced secretion of bile salts, or also from enhanced billary cholesterol secretion
what does cholelithiasis ( cholesterol gallstone disease) cause?
over saturation of bile with cholesterol( 90%) duct, and blocked cystic duct
where are cholesterol gallstones commonly found?
cystic duct or in the AMPULLA OF VATER
what happens with the blockage of bile ducts?
lead to reduced digestion of lipids and also impairs the release of conjugated BILIBRUBIN and leads to obstructive JAUNDICE
what is alkaline phosphatase?
serum marker from the irritated and blocked bile ducts
What is steatorrhea?
fat in feces
What happens in Primary Lactose intolerance?
lactase activity is highest in infants and 90 % of lactase declines with age ( the diet should be low in lactose)- fermentation, leads to dehydration
what is secondary lactase?
due to damage or loss of intestinal mucosal cells EX. food poisoning
What is the most severe lactase deficency?
Cogenital lactase deficiency
Why is lactose found inthe Large intestine a bad thing?
because it is not suppose to be there, it was supposedtobe cleaved by lactase in the small intestine
What happens in secondary lactose?
severe diarrhea or gastroenteritis due to ROTAVIRUS and can lead to intestinal injury
What disease does secondary lactose intolerance cause?
Celiac disease is a immune mediated damage in response to gluten ( proteins in grains)
What type of disorder is congential lactase deficiency?
autosomal recessive
what happens in congential lactase deficency?
Ingestio og milk would lead to severe diarrhea and dangerous dehydration or even death!
What are the cells found in the duodenum?
Gastrin, parietal, mucus, chief, epithelial mucousal,bile salts,pancreatic lipase
What do G cells produce?
Gastrin
where is Gastrin found?
in the antrum of stomach
What does gastrin release?
Gastric acid
What do cheif cells produce?
pepsinogen, and gastric lipase
What is pepsinogen when it is activated?
Pepsin
what type of enzyme is pepsin?
endopeptidase
pepsin does enzymatic proteolysis by?
helping to cleave mor pepsinogen
where is pepsinogen found?
the pancreas
where is pepsin found?
it is found in the lumen of the stomach
from the chief cell, gastric lipase is produced to do what?
cleaveTAGS with medium chain fatty acid
What arethe two thing that parietal cells produce?
HCL, intrinsic factor
what does HCL do?
it denatures proteins and kills bacteria and fungi because of low acidic pH
what does the intrinsic factor do from parietal cells?
it secrets B12
Where is the intrinsic factor B12 secreted?
In the ilieum
What cells are found n the duodenum?
epithelial mucosal cells
What do epithelial mucosal cells do?
they make secretin which stimulates pancreatic HCO3 secretion
what does Cholecystokinin do?
it stimulates gallbladder emptying, inhibits gastric mobility, and activates ENTEROPEPTIDASE
what are the enteropeptidases?
Trypsin, Chymotrypsin, Elastase, Colipase, Phospholipase A
what do enteropeptidases do?
cleave proteins at the COOH end of specific amino acids
what does trypsin cleave?
cleaves Arg or Lys ( both have a positive charge)
What is trypsin stopped by?
trypsin is stopped by trypsin inhibitor protein, and the the inhibitor protein is digested in the duodenum
Does trypsin have a long and narrow pocket?
yes
Where is trypsin active?
in the duodenum
what typeof pocket does chymotrypsin have?
It is wide and large
What does chymotrypsin do?
cleaves after bulky aromatic
what does elastase cleave?
gly, ala, ser
what kind of pocket does elastase have?
small pocket
why is colipase needed ?
it is needed to anchor pancreatic lipase
What does colipase do?
pushes bile salts away from TAGS and anchors pancreatic lipase to lipid droplets
What does bile salts do?
transport free cholesterol from liver to duodenum
where is bile produced?
in the liver / hepatic billary canaliculi
what are the contents of bile?
glycine, taurine, PC, free cholesterol, bilrubon
what phospholipids does bile contain?
PC- improves solubility of free cholesterol
What enzyme is found in the duodenum?
Pancreatic lipase
what does pancreatic lipase do ?
forms molecule that can enter intestinal mucosal cell(MAG)
what is pancreatic lipases function?
digestion of TAGs
what does pancreatic lipase need?
it requires bile salts and lyso-PC
what salts do bile make?
Bile salts
where are bile salts released?
in the caniliculi by active transport via ABC transporter
what are Bile salts formed with?
formed in the liver with bile acids and gly or taurine
what are the 2 primary bile acids?
cholic acid, chenodeoxycholic acid
what does cholic acid produce?
deoxycholic acid
whats does chenodeoxycholic acid produce?
lithocholic acid
what is the precursor of bile salts when it is synthesized denovo?
cholesterol
what are bile salts used for?
to emulsify the dietary lipids for digestion=(chyme)
how do bile salts reach the liver reach the liver?
enterohepatic circulation
what charge do bile salts have?
negative
what will happen if you have a high purine diet?
increase in uric acid
why is it bad to have an increase in uric acid?
will cause formation of crystals in your tissues, gout,and kidney stones
