LDL/HDL/Chylomicron question

[Fungi121]

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Wasn't sure if I should've put this in MCAT Q&A, but yeah.....!

Anyways, once fat reaches the small intestine, I know that chylomicrons go into the lymph then to the veins in the neck.

But what about LDLs and HDLs? Where do those end up going? I know they are made in the liver, but then where do they go after that? I'm so confused on this >_<

EDIT: Does it go straight from the liver into the bloodstream?

 

[LianaStan]

Yes, LDL and HDL are found freely in the bloodstream. LDL plays a role in delivering cholesterol to cells throughout the body as cholesterol is important for a variety of cellular processes and synthetic pathways. HDL's main role is to transport cholesterol back to the liver. This is why HDL is considered a 'good cholesterol' (though current studies on this reveal a much more complex characterization) because it can remove excess cholesterol that may be deposited along arteries (this is caused by LDL's deposition of cholesterol in blood vessel walls, potentially causing arteriosclerosis).

Edit: This is the simplified pathway taught in many introductory bio courses. I also think this will be the easiest way to think of the lipoproteins; anything more complex than this I would assume would be provided through a passage on the MCAT.