In intestinal villi, lacteals absorb long-chain fatty acids as chylomicrons into which system?

• A. Portal vein
• B. Systemic circulation via aorta
• C. Pulmonary circulation
• D. Lymphatic system

Answer: (D)

Long-chain fats are processed in the intestinal mucosa into chylomicrons, which are large lipid-protein particles. These chylomicrons are too big to enter blood capillaries in the villi, so they are taken up by the lacteals, the lymphatic capillaries inside the villi. They travel through the lymphatic system, ultimately joining the bloodstream via the thoracic duct and then the left subclavian vein. This makes the lymphatic system the primary route for these fats right after absorption. Other routes, like the portal vein or pulmonary circulation, don’t handle these large lipid particles at this stage, and systemic circulation via the aorta isn’t the initial path from the intestinal villi.