Cam T. Phan and Patrick Tso

Department of Pathology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267

FIGURES

Figure 1. Classification of lipids based on their ability to interact with water. Non-polar Lipids: octadecane, carotene, squalene, cholesteryl oleate, cholesteryl linoleate, and paraffin oil. Polar Lipids: I. - triacylglycerols, diacylglycerols, long-chain protonated fatty acids, and fat-soluble vitamins. II. - phospholipids, monoacylglycerols, monoethers, and alpha-hydroxy fatty acids. IIIA. - sodium salts of long-chain fatty acids, many anionic, cationic and nonionic detergents, and lysophosphatidylcholine. IIIB. - bile salts, sulfated bile alcohols, and saponins (6).

Figure 2. Lingual and gastric lipase activity levels in different species. Data are mean ± SEM of 2 to 3 animals for each species (276).

Figure 3. Hydrolysis of medium- (C 8:0) and long- (C 18:1) chain triglyceride by rat lingual lipase. The assay system contained 1 micromole of either glycerol tri(³H)oleate or tri(¹⁴C)octanoate; incubation was for 30 min. (29).

Figure 4. Localization of lipase in the human stomach-the level of lipolytic activity in the gastric mucosa of four sampling sites (33).

Figure 5. Diagrammatic representation of the consequences of antral peristalsis (277).

Figure 6. Diagrammatic representation of the effect of bile salt micelles (or vesicles) in overcoming the diffusion barrier resistance by the unstirred water layer. In the absence of bile acids, individual lipid molecules must diffuse across the barriers overlying the microvillus border of the intestinal epithelial cells (arrow 1). Hence, uptake of these molecules is largely diffusion limited. In the presence of bile acids (arrow 2), large amounts of these lipid molecules are delivered directly to the aqueous-membrane interface so that the rate of uptake is greatly enhanced (124).

Figure 7. Pathways of triacylglycerol biosynthesis in the intestinal mucosa.