What is the final step in the lipid absorption process?

The final step in the lipid absorption process is the exocytosis of chylomicrons. After dietary lipids are emulsified by bile salts and broken down by pancreatic enzymes, they are absorbed by the intestinal epithelial cells. Inside these cells, fatty acids and monoglycerides are re-esterified to form triglycerides. These triglycerides, along with cholesterol and proteins, are then packaged into lipoproteins called chylomicrons.

Once formed, chylomicrons are transported to the basolateral side of the intestinal epithelial cells. They are then secreted into the lymphatic system through a process called exocytosis. This is crucial because chylomicrons are the primary vehicles responsible for transporting dietary lipids to various tissues in the body, where they can be utilized or stored.

Formation of micelles, while important for the solubilization and transport of lipids to the intestinal mucosa, occurs earlier in the absorption process and is not the final step. Re-esterification of lipids occurs as part of the processing within the epithelial cells, before the chylomicrons are formed and released. The release of bile salts is also not the terminal event in lipid absorption, as bile salts are involved earlier in the emuls