chylomicrons

[dmf2682]

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Hey all, why don't chylomicrons go straight to the liver via the hepatic portal vein, as opposed to going through the lymph and then into the jugular? Is that to dilute it so the liver isn't overwhelmed by fat? Thought about solubility, but since it ends up in the jugular I couldn't think of that being the reason. Just wondering.

 

[mcloaf]

Maybe there's an answer to this that I'm not aware of, but this seems like more of a "because that's the way it is" type of question.

 

[dmf2682]

Maybe there's an answer to this that I'm not aware of, but this seems like more of a "because that's the way it is" type of question.

There is a reason for everything.

 

[chiddler]

There is a reason for everything.

he's not saying otherwise. he's saying that it's just another biology fact that you have to know.

it's like asking "why is the kidney in its particular location?" there's probably an answer, but we don't care for the mcat.

 

[MedPR]

Hey all, why don't chylomicrons go straight to the liver via the hepatic portal vein, as opposed to going through the lymph and then into the jugular? Is that to dilute it so the liver isn't overwhelmed by fat? Thought about solubility, but since it ends up in the jugular I couldn't think of that being the reason. Just wondering.

The same reason why some of the blood goes from the aorta into the brachiocephalic trunk, some into the left common carotid, and some into the left subclavian. If something has multiple pathways, it will go to multiple places.

Edit: Also, the chylomicrons that enter lacteals will re-enter systemic circulation at the left brachiocephalic vein, not at the jugular vein.

 

[mcloaf]

There is a reason for everything.

I wish you the best of luck studying for the MCAT with that approach...

 

[MedPR]

I wish you the best of luck studying for the MCAT with that approach...

Not to be argumentative, but I think its a good approach so long as you focus on learning the reason behind the basic concepts.

For instance, knowing why a buffer works rather than just memorizing "buffers resist pH change," would be a good thing to do for MCAT 🙂

 

[mcloaf]

Not to be argumentative, but I think its a good approach so long as you focus on learning the reason behind the basic concepts.

For instance, knowing why a buffer works rather than just memorizing "buffers resist pH change," would be a good thing to do for MCAT 🙂

Well, I'm not arguing that you shouldn't try to understand things on a conceptual level for the MCAT--obviously you should. However, at some point you have to stop asking why and just get on with studying.

 

[dmf2682]

I wasn't really wondering because of the mcat per se, I was just curious. Jordan and Jon told me that it was the jugular, but they've been known to be wrong. Thanks for clarifying, medpr.

I went and asked the google and got an answer that makes sense. Large chylomicrons straight from the intestine (that are inserted into the systemic circ. system at the brachiocephalic vein, thanks again) circulate in the blood for a number of hours before they are taken up and broken down by the liver. What happens to them while they're in circulation is they are stripped down and reduced in size by lipid hungry tissues. Endothelial vascular cells on those tissues (website mentioned muscle as well as adipose and mammary) use lipoprotein lipase to take triglycerides out of the chylomicrons. When they've been reduced in size they can then be taken up by the liver and finally metabolized.

Probably way too much for the MCAT but I'm not planning on being a pre-med forever, and after 29 years of being around my brain hasn't stopped learning yet, so I may as well do it while I can! If you're interested I can send you the link but I found it on my phone but I'm on my air right now and am too lazy to post it.

night folks

 

[MedPR]

Well, I'm not arguing that you shouldn't try to understand things on a conceptual level for the MCAT--obviously you should. However, at some point you have to stop asking why and just get on with studying.

yea, I agree.

 

[mcloaf]

yea, I agree.

Heh, I've just been in way too many undergrad classes with overachieving premeds who cost themselves a lot of sleep and caused a lot of undue stress by asking "why" when they could've just buckled down, done the work, and gotten it over with. Not saying anybody in this thread is necessarily walking that road, but it's something watch out for.

 

[MedPR]

I wasn't really wondering because of the mcat per se, I was just curious. Jordan and Jon told me that it was the jugular, but they've been known to be wrong. Thanks for clarifying, medpr.

I went and asked the google and got an answer that makes sense. Large chylomicrons straight from the intestine (that are inserted into the systemic circ. system at the brachiocephalic vein, thanks again) circulate in the blood for a number of hours before they are taken up and broken down by the liver. What happens to them while they're in circulation is they are stripped down and reduced in size by lipid hungry tissues. Endothelial vascular cells on those tissues (website mentioned muscle as well as adipose and mammary) use lipoprotein lipase to take triglycerides out of the chylomicrons. When they've been reduced in size they can then be taken up by the liver and finally metabolized.

Probably way too much for the MCAT but I'm not planning on being a pre-med forever, and after 29 years of being around my brain hasn't stopped learning yet, so I may as well do it while I can! If you're interested I can send you the link but I found it on my phone but I'm on my air right now and am too lazy to post it.

night folks

Makes sense. I guess the liver doesn't have sufficient levels of lipase to process the large chylomicrons. I actually just learned about lymph in my anatomy class, so I a decent background in it. If you care, the brachiocephalic vein is just the anastomosis of the jugular vein and the subclavian vein. So I guess the lymphatic duct could drain into the jugular vein depending on the individual. My anatomy teacher said that the venous system is the most anomolous system in the human body.