SI Digestion & Absorption Part 2 (midterm) Flashcards
Pancreatic amylase is found in the ____ and breaks down starches/carbs. Pancreatic amylase came from ___________
SI, pancreatic juice
SI enzymes from crypts of lieberkuhn go to work on remaining disaccharides. What are the 3 SI enzymes that do this?
maltase, surcase, and lactase
maltase breaks down maltoses into 2 glucoses
sucrase breaks down sucroses into glucose and fructose
lactases breaks down lactose into galactose and glucose
note: for lactose intolerant patients they would have low supply of lactase
Which enzyme is found in the mouth and digests carbs?
salivary amylase
Does the esophagus or stomach digest carbs?
NO
In the duodenum, there is pancreatic amylase and brush border enzymes to help with the digestion of carbs. What does pancreatic amylase breakdown specifically?
oligosaccharides
In the duodenum, there is pancreatic amylase and brush border enzymes to help with the digestion of carbs. What are the brush border enzymes and what do they breakdown?
test q
destrinase and glucoamylase break down oligosaccharides
maltase, sucrase, and lactase breakdown disaccharides into monosaccharides
In the duodenum, there is pancreatic amylase and brush border enzymes to help with the digestion of carbs. Most of the carbs are absorbed as…
test q
monosaccharides
In the duodenum, there is pancreatic amylase and brush border enzymes to help with the digestion of carbs. Most carbs are absorbed as monosaccharides. What monosaccharides are absorbed through secondary active transport and which are through facilitated diffusion?
test q
glucose is absorbed through sodium cotransport (secondary active transport)
fructose is absorbed through a simple diffusion with carrier protein known as facilitated diffusion
note: if you don’t have enough sodium, then you cannot absorb glucose!!
What else is cotransported with sodium, besides glucose?
AAs
_______ denatures or unfolds proteins in the stomach and __________ turns proteins into peptides
HCl, pepsin
T/F: the pancreas produces enzymes for 3 of the food categories: carbs, lipids, proteins
test q
true!!!!
What digestive enzymes are made in the pancreas that will go to the small intestine?
amylase, lipase, and proteases
In the small intestine, there are brush border enzymes (__________) which help with the digestion of proteins. Most are absorbed as dipeptides, tripeptides, and as free AAs. Smaller AAs are cotransported with sodium. Some larger AAs and peptides are transported by membrane transport proteins
test q
peptidases
Why aren’t AAs absorbed by diffusion?
-because they’re amiphatic
-because some have a charge
Which enzyme begins the digestion of lipids and where?
lingual lipase is found in the mouth
Where does most lipid digestion occur for adults?
small intestine
Where does bile come from?
gallbladder
Most lipid digestion in adults occurs in the SI. Lipids are emulsified in the SI by bile of globules of triglycerides. What does pancreatic lipase do here?
splits TGs into FAs and MGs
Are there lipases in the brush border?
NO
Most lipid digestion in adults occurs in the SI. Lipids are emulsified in the SI by bile of globules of triglycerides. Pancreatic lipase splits TGs into FAs and MGs. MGs and FAs are then carried in ________ that are covered in bile to surfaces of microvilli. Fats diffuse from micelles to the interior of enterocytes of the microvilli. Fats become incorporated into the ER and are formed into TGs and transported as ______________, while micelles remain in chyme. Short and medium chain TGs (relatively more water soluble) are either absorbed directly into ________ or by lymphatics
test q
micelles, lymph chylomicrons, portal blood
T/F: cell membranes allow lipid soluble molecules through
true
Lymphatic capillaries are called lacteals in regards to digestion. They have cells that overlap which allow chylomicrons to get through and will then go to the ______________ and then liver
thoracic duct
What enzymes are found in pancreatic juice and helps with the digestion of nucleic acids?
ribonuclease and deoxyribonuclease
What brush border enzymes help with digestion of nucleic acids?
nucleosideases and phosphatases
