Where are chylomicrons formed, and how do they reach the bloodstream?

Where are chylomicrons formed, and how do they reach the bloodstream?

• A. Formed in enterocytes; transported directly into the portal vein
• B. Formed in enterocytes; released into the bloodstream via the thoracic duct
• C. Formed in enterocytes; transported into the lymphatic system via lacteals and then into the bloodstream via the thoracic duct
• D. Formed in liver; released into the hepatic artery

Answer: (C)

Chylomicrons are formed in the enterocytes of the small intestine from dietary fats. Because they are large particles, they don’t enter the tiny blood capillaries in the intestinal lining. Instead, they are released into the lymphatic system through the lacteals, the lymphatic capillaries in the villi. The lymph carries these chylomicrons to the thoracic duct, which drains into the bloodstream at the left subclavian vein. So, chylomicrons reach the bloodstream by first traveling through the lymphatic system, bypassing the hepatic portal vein, before entering systemic circulation.

Chylomicrons are formed in the enterocytes of the small intestine from dietary fats. Because they are large particles, they don’t enter the tiny blood capillaries in the intestinal lining. Instead, they are released into the lymphatic system through the lacteals, the lymphatic capillaries in the villi. The lymph carries these chylomicrons to the thoracic duct, which drains into the bloodstream at the left subclavian vein. So, chylomicrons reach the bloodstream by first traveling through the lymphatic system, bypassing the hepatic portal vein, before entering systemic circulation.