Term
| What is the major caloric source of fat in our diets? |
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Definition
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Term
| What is the source of Phospholipids, sterols, sphingolipids, galactolipids, and carotenoids that we ingest? |
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Definition
| Membranes of cells that we eat |
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Term
| What is the average U.S. fat intake? |
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Definition
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Term
| How long does it take to absorb dietary fat into the circulatory system? |
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Definition
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Term
| Where are Acid lipases found? |
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Definition
| Lingual glands and Gastric mucosa |
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Term
| The pancreas secrets which lipases? |
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Definition
| Pancreatic lipase-colipase, Carboxy ester lipase, and Phospholipase A2 |
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Term
| Acid lipases account for how much lipid digestion in a normal adult? |
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Definition
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Term
| What is the action of acid lipase on triglycerides? |
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Definition
Tend to cleave one ester bond of a triglyceride leaving a fatty acid and a diglyceride.
Important to note is that the acid lipases can cleave more then one bond but typically only achieve the above action due to timing (compensatory digestion occurs in patients with pancreatic deficiency) |
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Term
| How does the fat emulsify so that acid lipases can work efficiently? |
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Definition
| Hydrophobic interactions combined with gastric contractions help to emulsify the fat |
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Term
| What triggers the release of CCK? |
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Definition
| Fatty acids from acid lipase lipolysis |
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Term
| What is the function of CCK? |
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Definition
| To trigger release of pancreatic juice and bile salts |
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Term
| How do newborns digest fat, given that they do not have high levels of pancreatic enzymes? |
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Definition
| Compensatory action from acid lipases as well as human milk lipase |
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Term
| In patients with pancreatic insufficiency, what happens to enzymatic activity? |
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Definition
| Compensatory action from acid lipases allows for some absorption of fat (not as efficient as pancreatic lipases, but higher activity than normal) |
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Term
| What type of action does the Pancreatic lipse-colipase system have? |
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Definition
| This enzyme will only cleave the 1 or 3 ester bond making 2 fatty acids and a 2-monoglyceride |
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Term
| What is the optimal pH for Acid lipases? |
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Definition
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Term
| What is the optimal Ph for Pancreatic and milk lipases? |
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Definition
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Term
| Gastronoma's can have what effect on lipolysis enzymes? |
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Definition
| Gastronoma's can end up secreting gastric acids in areas of pancreatic digestion. This can denature the pancreatic enzymes |
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Term
| What is the effect of bile salts on Pancreatic lipase? |
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Definition
| Diminishes action of Pancreatic lipase |
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Term
| What is the function of colipase? |
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Definition
| To help reintroduce pancreatic lipase when displaced by bile salts |
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Term
| What is the action of Carboxyl esterase? |
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Definition
| Non-specific like acid lipases. The end result of lipolysis by Carboxyl esterase is 3 fatty acids and glycerol. This enzyme can also lipolzye cholesterol esters |
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Term
| What is the action of phospholipase A2? |
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Definition
| Will work on phospholipids cleaving off one fatty acid |
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Term
| What is the effect of bile salts on Carboxyl ester lipase and phospholipase A2? |
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Definition
| activity increases because the enzymes cannot to favorably reach the bonds until they are in micelles |
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Term
| What do bile salts disperse? |
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Definition
| the PRODUCTS of lipolysis. You will not find triglycerides in bile salts |
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Term
| Besides helping Carboxyl ester lipase and phospholipase A2, what other important effect do bile salts have on fat digestion? |
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Definition
| Greatly increase the water solubility of fatty acids |
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Term
| What other important factors can "hitch a ride" on the fatty core of bile salt micelles? |
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Definition
| cholesterol, drugs, carcinogens, etc |
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Term
| What is the effect of consuming plant sterols on dietary cholesterol absorption? |
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Definition
| Plant sterols compete with cholesterols reducing the amound of cholesterols that are taken up |
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Term
| What happens in the cyle of bile salts? |
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Definition
| Highly conserved, very low levels of bile salts are lost in the feces but the liver readily replaces it |
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Term
| Where is active absorption of bile salts taking place? |
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Definition
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Term
| Where is active absorption of fat occuring in the intestine? |
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Definition
| No where, it is all passive absorption |
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Term
| What are the three enzymes of TG Synthase? |
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Definition
| Acyl-Coa Synthetase, MG-acyltransferase, DG acyltransferase |
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Term
| What is the function of Acyl-Coa synthethase? |
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Definition
| Attaching an SCoA to a fatty acid, making an "Active fatty acid" |
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Term
| What are the two pathways of triglyceride synthesis? |
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Definition
| Via TG synthethase or via Phosphatidic Acid |
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Term
| What is the path of Chylomicrons? |
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Definition
| Travel along lymphatic system and dump into the subclavian vein where they then make their way towards the liver |
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Term
| How do fat soluble vitamins and carcinogens travel across the intestinal membrane? |
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Definition
| Via the bil-salt micelles |
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Term
| What are the three general ways you can have fat malabsorption? |
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Definition
Intraluminal
Mucosal
Lymphatics |
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Term
| What are the common intraluminal defects? |
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Definition
Lipase/colipase deficiency
miceller dispersion
-bile salt issues
pH regulation |
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Term
| Whats the most common cause of chronic pancreatitis? |
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Definition
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Term
| What are the effects of chronic pancreatitis? |
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Definition
decreased pancreatic HCO3 causing pH disregulation
pancreatic enzymatic insufficiency |
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Term
| What percent of lipase action do you need to lose before you have an noticable effect on fat absorption? |
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Definition
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Term
| What is unique about fat absorption of medium chain length fatty acids? |
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Definition
| Can pass through the membrane via diffusion and therefore do not need to be converted |
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