Q. What is the special route that lipids follow during digestion? What are chylomicrons?
Triglycerides emulsified by the bile within micelles suffer the action of lipases that break them into glycerol and fatty acids. Fatty acids, cholesterol and glycerol are absorbed by the intestinal mucosa. In the interior of the mucosal cells glycerol and fatty acids form again triglycerides that together with cholesterol and phospholipids are packed in small vesicles covered by proteins and called as chylomicrons. The chylomicrons are released in minuscule lymphatic vessels not in blood vessels and they gain the lymphatic circulation, so the lymphatic system plays an important role in the absorption of lipids.
The lymphatic circulation drains its content to the venous blood circulation in that manner chylomicrons reach the liver where their lipid content is released and processed in the blood under the form of protein-containing complexes called lipoproteins, like HDL, LDL and VLDL.