Biology Question (digestion)

[TawMus]

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Ok, so CCK is secreted into the duodenum in the presence of chyme. The subsequent secretion leads to release of bile, slowing down of gastric movement, and release of pancreatic enzymes. Could someone tell me what the exact enzymes that are caused to secrete by CCk are? Are they the pancreatic proteases? or Pancreatic amylase/lipase/nuclease?? Or are they just the brush border enzymes. Thanks.

 

[rocuronium]

From what I can remember, CCK causes the release of bile and pancreatic enzymes.

Enzymes from the pancreas include peptidases (trypsin, chymotrypsin), nucleases and amylase. I would assume that they are all released when the pancreas is stimulated by CCK.

 

[RySerr21]

Ok, so CCK is secreted into the duodenum in the presence of chyme. The subsequent secretion leads to release of bile, slowing down of gastric movement, and release of pancreatic enzymes. Could someone tell me what the exact enzymes that are caused to secrete by CCk are? Are they the pancreatic proteases? or Pancreatic amylase/lipase/nuclease?? Or are they just the brush border enzymes. Thanks.

in human phys we learned about 3 main hormones released in response teo a meal... CCK, GIP, and secretin. the amount of each secreted depends on the content of the meal. CCK is a hormone released in response to fat. the more fatty the meal, the fattier the chyme and the more CCK will be released. this makes sense b/c fats take longest to digest, and as you already said one of the functions is to slow down gastric movement. so the fattier the chyme, the more CCK, the more bile (to emulsify the fat), and the slower the gastric movement

that being said, CCK's main role as far as enzymes is to stimulate the release of enzymes that will help breakdown lipids.... aka pancreatic lipase from the pancreas.

secretin release is the one that will stimulate pancreatic amylase b/c it is the one that is released in response to carbs.

GIP works with proteins (i think) so im it might stimulat release of other proteolytic enzymes like trypsin, carboxypeptidase, and elastase but im not exactly sure on that one.

 

[Kaustikos]

From what I can remember, CCK causes the release of bile and pancreatic enzymes.

Enzymes from the pancreas include peptidases (trypsin, chymotrypsin), nucleases and amylase. I would assume that they are all released when the pancreas is stimulated by CCK.

CCK is related to chyme/bile, so it has nothing to do with releasing protein-breaking enzymes/carbohydrate breaking enzymes. Thus, you can cross out peptidases/amylases.

Just remember that CCK is related to bile release. Bile release is to emulsify fat into micelles. Micelles contain lipases -the only enzyme to concern yourself with in regads to CCK.

 

[rocuronium]

Good to know. Thanks for the clarification.

 

[TawMus]

CCK is related to chyme/bile, so it has nothing to do with releasing protein-breaking enzymes/carbohydrate breaking enzymes. Thus, you can cross out peptidases/amylases.

Just remember that CCK is related to bile release. Bile release is to emulsify fat into micelles. Micelles contain lipases -the only enzyme to concern yourself with in regads to CCK.

Are you sure about CCK not relating to release of pancreatic release of enzymes? I have a direct quote from a book relating the release of CCK with release of pancreatic zymogens. (chymotrypsinogen/procarboxypeptidase/procollagenase)

 

[RySerr21]

Are you sure about CCK not relating to release of pancreatic release of enzymes? I have a direct quote from a book relating the release of CCK with release of pancreatic zymogens. (chymotrypsinogen/procarboxypeptidase/procollagenase)

edit: just looked in my physiology text book. it doesnt specify any of the zymogens you mentioned. it just says stimulates release of digestive enzymes from the pancrease, most importantly panreatic lipase for breakdown of fat.

that being said, if you are having trouble deciding who to trust, a textbook or somoene on an anonymous forum, i'd go with the textbook every time.

 

[Kaustikos]

Are you sure about CCK not relating to release of pancreatic release of enzymes? I have a direct quote from a book relating the release of CCK with release of pancreatic zymogens. (chymotrypsinogen/procarboxypeptidase/procollagenase)

edit
i'm an idiot.
Disregard what I have been saying.

 

[TawMus]

edit: just looked in my physiology text book. it doesnt specify any of the zymogens you mentioned. it just says stimulates release of digestive enzymes from the pancrease, most importantly panreatic lipase for breakdown of fat.

that being said, if you are having trouble deciding who to trust, a textbook or somoene on an anonymous forum, i'd go with the textbook every time.

Well, could it be possible that your textbook is refering to the zymogens??(the zymogens are basically enzymes, just inactive forms that are activated by trypsin) Also, there are 3 others pancreatic enzymes that are also released ( Pancreatic amylase, pancreatic lipase, and pancreatic nuclease) are these stimulated by the CCK also??

 

[RySerr21]

Well, could it be possible that your textbook is refering to the zymogens??(the zymogens are basically enzymes, just inactive forms that are activated by trypsin) Also, there are 3 others pancreatic enzymes that are also released ( Pancreatic amylase, pancreatic lipase, and pancreatic nuclease) are these stimulated by the CCK also??

pancreatic lipase is CCK. pancreatic amylase is stimulated by secretin (another hormone). i'm not sur eabout pancreatic nuclease.

tryspin is also released as a zymogen (trypsinogen), thats why i am a little confused. it doesnt become trypsin until it interacts with enterokinase which is released by the small intestine. once it becomes trypsin, then it activates the other zymogens. enterokinase is released whenever food enters the duodenum, regardless of what it is. so you have all theze zymogens that are inactive. you eat something, it goes from the stomach to the duodenum, stimulates enterokinase to be relased, which converts trypsinogen into trypsin, which then actiates everything else. make sense?

 

[TawMus]

Yea, I get what you're saying. But then, what stimulates the release of these pancreatic zymogens?

 

[RySerr21]

Yea, I get what you're saying. But then, what stimulates the release of these pancreatic zymogens?

good question. haha. maybe they are just being released during times of relaxation and hanging out in the intestine, waiting for enterokinase. ive never seen anyting that stated what exactly stimulated the release of the zymogens.

 

[TypeSH07]

Sort of a related basic question that may seem stupid. In the intestines do nutrients go from the lumen(inside) to the outside so that they can be absorbed in blood? Or is it the other way around? Cavity to lumen to blood?

 

[BloodySurgeon]

Sort of a related basic question that may seem stupid. In the intestines do nutrients go from the lumen(inside) to the outside so that they can be absorbed in blood? Or is it the other way around? Cavity to lumen to blood?

If we are talking about absorption then it is going to body fluid (i.e. blood) and that means from lumen to blood. But there are ways things can get from our blood to our intestines and reabsorped back into the blood again in a cyclic pattern.