CONTENTS IX 



II. The Digestion and Absorption of Fats in the Gastrointestinal Tract 



(continued) 



4. The Pathways for Lipid Absorption 115 



(1) The Sites of Absorption in the Gastrointestinal Tract 115 



a. Mouth 115 



b. Stomach 115 



c. Small Intestine 117 



d. Large Intestine 117 



(2) Anatomical Features of the Small Intestine of Importance in Ab- 



sorption 117 



a. The Surface Structure of the Small Intestine 117 



b. The Histological Structure of the Intestinal Mucosa 120 



5. Methods for the Study of Fat Absorption and Lipid Absorption in Gen- 



eral 123 



(1) Thiry-Vella Fistulas 123 



(2) Cori Technic 126 



a. Method of Irwin, Steenbock, and Templin 127 



b. Method of Deuel, Hallman, and Quon 127 



(3) Other Methods for the Study of Fat Absorption 129 



a. Cannulation of the Thoracic Duct 129 



b. Chylomicron Method 130 



c. Hemolipokrit Method 132 



d. Studies on the Portal Blood 133 



e. Roentgenologic Method for the Study of Fat Absorption 133 



f . The Use of Radioactive Iodinated Fat 133 



g. Elaeostearic Acid as a Tracer for the Study of Fat Absorption . . . 134 



6. The Digestion of Fats 134 



( 1 ) Digestion in the Stomach 135 



(2) Digestion in the Small Intestine 136 



a. The Action of Lipases 136 



b. The Extent of Hydrolysis of Fats 137 



c. The Bile Requirement 141 



7. The Absorption and Transport of Fats 142 



(1) The Absorption of Fats from the Gastrointestinal Tract 142 



a. Introduction 142 



b. Theories of Fat Absorption 144 



(a) Early Theories on Fat Absorption 144 



(b) Lipolytic Theory (Verzar) 146 



a'. The Hydrotropic Action of Bile Salts 147 



b'. Phosphorylation and Absorption ' 148 



(c) Partition Theory (Frazer) 151 



a'. Emulsification 151 



b'. Hydrolysis 153 



c'. The Passage of Fat through the Outer Border of the In- 

 testinal Cell 154 



d'. Adrenalectomy and Fat Absorption 156 



