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21 Cards in this Set
- Front
- Back
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What are the 3 ways that the small intestine tries to maximize/amplify its surface area for absorption?
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1. folds of Kerkring
2. microscopic villi and crypts of lieberkuhn 3. submicroscopic microvilli |
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Where are most carbs, proteins, and lipids absorbed?
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duodenum
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What enzyme is used to digest amylose? What are the products? where does it start working?
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alpha-amylase
maltotriose and maltose mouth and orad stomach |
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what enzyme is used to digest amylopectin (plant starch)? what are the products of digestion?
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alpha-amylase
maltotriose, maltose, alpha-limit dextrin (1-6 links can't be broken) |
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What 3 enzymes are found on the brush border; what do they work on and what are their products?
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1. Lactase: breaks down lactose into glucose and galactose
2. Glucoamylase: breaks down maltose and maltotriose into glucose 3. sucrase-isomaltase: breaks down sucrose and alpha 1,6-limit dextrans into glucose and fructose |
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Fructose enters the enterocyte via what channel?
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GLUT5
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Glucose and galactose enters the enterocyte via what channel? What is its mode of action?
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SGLT-1
secondary active transport so if a kid is glucose intolerants (sucks!) don't try to give them any galactose....they use the same transporter. |
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True/False: The rate limiting step of absorption of carbohydrates is UPTAKE
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true!!!
it's NOT hydrolysis! |
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You have malabsorption/maldigestion.
What happened to you? What are some examples of a digestive enzyme deficiency? What about transport deficiency? |
Digestive enzyme: lactase, chronic alcoholism
transport: defect in SGLT-1 maybe you have celiac dz, bacterial/protozoan infection. |
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What transporter is used on the basolateral side of the enterocyte for nutrients to enter bloodstream?
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GLUT2
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In order to digest protein in the lumen, you need what 2 kinds of proteases?
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1. gastric
2. pancreatic |
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where and how does protein digestion begin?
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it starts in the stomach with pepsin
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What are the 2 classes of pancreatic proteases, and which enzymes are included in both?
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Endopeptidases: trypsin, chymotrypsin, elastase
Exopeptidases: carboxypeptidase A and B |
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What is needed to convert trypsinogen into trypsin?
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enterokinase!!!
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what does trypsin do?
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it converts precursors to active proteases.
chymotrypsinogen-->chymotrypsin proelastase-->elastase procarboxypeptidase A&B-->carboxypeptidase A&B |
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what happens if you have pancreatitis?
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you have premature activation of trypsinogen so you activate all these proteases and you autodigest your pancreas.
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where does pepsinogen come from and how does it get converted to its active form of pepsin?
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pepsinogen is secreted by chief cells (after they're stimulated by vagus). H+ (from parietal cells that are also stimulated by vagus) then causes the conversion from pepsinogen to pepsin.
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What is the name of the cotransporter that is used to bring large peptides into the cell?
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PepT1
(H/oligopeptide) |
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___and ____peptides are absorbed better than free amino acids. They use what transporter?
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Di and tripeptides
they use PepT1 |
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list the hormonal triggers and actions that facilitate protein assimilation
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acetylcholine (Ach)-->vagus
secretin to get pancreatic enzymes |
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How is protein handled after luminal digestion
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1. free amino acid goes straight through
2. di/tri peptides can go straight through 3. di/tri peptides can go back into cytoplasm and get broken down some more. |
