MICROVILLI OF ENTEROCYTE ACID MICROCLIMATE BULK PHASE DISEQUILIBRIUM ZONE Free long-chain Bile salt AA sn-2 Monoacylgly fatty acid L C (2-MAG K I A D Free short- chain fatty acid N DH O OH Mixed micell Emulsion droplet Diffusion of micelles FAT/CD36 sn-2 Monoacylglycerol Bile salt (2-MAG) micelle 微粒转运脂肪分解产物到肠细胞表面 Micellar transport of lipid breakdown products to the surface of the enterocyte. Mixed micelles carry lipids through the acidic unstirred layer to the surface of the enterocyte. 2-MAG fatty acids, lysophospholipids and cholesterol leave the mixed micelle and enter an acidic microenvironment (at nEE) created by an apical Na-H exchanger the acidity favors the protonation of the fatty acids. the lipids enter the enterocyte(脂类进入肠细胞的三条途径)by(1) nonionic diffusion(非离子扩散),(2) incorporation into the enterocyte membrane( collision)(嵌入肠细胞膜),or(3) carrier-mediated transport(载体介导转运)微粒转运脂肪分解产物到肠细胞表面 Micellar transport of lipid breakdown products to the surface of the enterocyte. Mixed micelles carry lipids through the acidic unstirred layer to the surface of the enterocyte. 2-MAG, fatty acids, lysophospholipids, and cholesterol leave the mixed micelle and enter an acidic microenvironment（酸性 微环境）created by an apical Na-H exchanger. The acidity favors the protonation of the fatty acids. The lipids enter the enterocyte（脂类进入肠细胞的三条途径）by (1) nonionic diffusion（非离子扩散）, (2) incorporation into the enterocytemembrane (collision)（嵌入肠细胞膜）, or (3) carrier-mediated transport（载体介导转运）