What structures aid in the absorption of fat into intestinal cells?

Micelles play a crucial role in the absorption of fat into intestinal cells. When dietary fats are consumed, they undergo emulsification and digestion, breaking them down into smaller molecules like fatty acids and monoglycerides. These molecules are hydrophobic and would not readily diffuse into the aqueous environment of the intestinal lumen.

Micelles are formed in the intestinal lumen and consist of bile salts and lipid digestion products. They encapsulate fatty acids and monoglycerides, surrounding these hydrophobic molecules with a hydrophilic surface that allows them to remain suspended in the aqueous environment. This arrangement facilitates the transport of lipids to the brush border of the intestinal cells (enterocytes).

Once the micelles reach the brush border, the fatty acids and monoglycerides can diffuse through the cell membrane of the intestinal cells. Inside the cells, they can be reassembled into triglycerides and packaged into lipoproteins, which then enter the lymphatic system via lacteals. Therefore, micelles are essential for the effective absorption of fats, as they enable the transport of insoluble fats in a soluble form.