What is the lipid-transporting particle formed by enterocytes that enters the lymphatic system?

• A. Chylomicrons
• B. VLDL
• C. LDL
• D. HDL

Answer: (A)

Dietary fats absorbed by enterocytes are repackaged into large lipoprotein particles called chylomicrons. These chylomicrons are formed in the intestinal mucosa by re-esterifying fatty acids and monoglycerides into triglycerides and loading them with specific apolipoproteins. They are then secreted from enterocytes into the intestinal lymphatic vessels (lacteals) rather than directly into the portal blood. From the lymph, they drain into the thoracic duct and enter the bloodstream, where they deliver triglycerides to tissues via lipoprotein lipase on capillary walls, leaving behind remnants cleared by the liver. This lymphatic route is what distinguishes chylomicrons from other lipoproteins like those produced by the liver, which enter the blood directly. The large size and dietary origin of chylomicrons, along with their entry into the lymphatic system, define them as the lipid-transporting particles formed by enterocytes.