Afferent and efferent blood flow in intestinal villi

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cornpops21

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FYI: I'm looking at the EK Bio page 123. The picture of the villus.

Can anyone explain the difference/importance of afferent and efferent blood flow in the intestinal villi, and how it relates to lacteals? Digestion/absorption of fats kinda confuses me. :confused:

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efferent blood flow will take absorbed nutrients to the liver via the hepatic portal vein.
afferent vessels are coming into the intestines from the abdominal aorta to supply those intestinal cells with nutrient/gas exchange.

the lacteals are capillaries of the lymphatic system. they absorb fat from the intestines.

of course it gets much more detailed than that...but that should suffice for the MCAT =]
 
Amino acids and glucose are transported to the liver by hepatic portal vein, but lipids use a completely separate process.

*first, fatty acids and monoacylglycerols enter epithelial cell in intestinal lining.

*Reassembled as triacylglycerols in the smooth endoplasmic reticulum.

*Triacylglycerols get packaged with absorbed cholesterol and phospholipids in protein covered fat droplets (chylomicrons), which first go through interstitial fluid and are then absorbed by lacteals in the villus.

*Once in he lymph, they head to the subclavian veins and dump into the circulatory system.

This is how most get into the blood. A much smaller portion enter the blood directly through the capillaries in the villus.
 
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