How Are Triglycerides and Cholesterol Absorbed?

Absorbing lipids into the body requires special consideration. Since the blood is water-based, how can these water-insoluble substances circulate? Cells lining the wall of the small intestine reassemble triglycerides and package them up along with cholesterol into shuttles called chylomicrons. Chylomicrons can leave these cells and enter the lymphatic circulation before enter the blood. Chylomicrons are very large and are unable to squeeze through the entry holes to the blood stream. Instead they drain into the larger openings to the lymphatic circulation. Within minutes, chylomicrons will circulate to a duct in the chest that gives them access to the blood (Figure 5.7). Once in the blood, a chylomicron will circulate for about a half hour, delivering its lipid bounty to tissue throughout the body.