During lipid absorption, lipids are exocytosed into which system before entering the bloodstream?

During lipid absorption, dietary lipids, primarily in the form of fatty acids and monoglycerides, are emulsified by bile salts in the intestine, allowing them to be absorbed by the intestinal epithelial cells. Once inside these cells, lipids are re-esterified into triglycerides and packaged into lipoprotein particles called chylomicrons.

These chylomicrons are then exocytosed from the epithelial cells into the lymphatic vessels, which are specialized channels that transport lymph, a fluid that helps in the absorption of dietary fats. The lymphatic system plays a crucial role in lipid absorption because it allows these large lipoprotein particles to bypass the liver initially and enter the bloodstream indirectly. The chylomicrons travel through the lymphatic vessels, eventually draining into the bloodstream via the thoracic duct, where they can circulate and deliver triglycerides to tissues throughout the body.

The other options represent different systems or processes not directly involved in the initial transport of lipids after absorption from the intestines.