The Physical Processes of Digestion

Description

This book is aimed at physiologists, pharmacologists, nutritionists and food technologists whose work requires an understanding of the physical processes of digestion. The book provides an overview of what is known of the physical processes of digestion in man and other simple-stomached vertebrates in two broad sections. The first section considers the physical constraints that govern the dissolution and digestion of the various macronutrients within food particles, and the physical factors that influence their subsequent transfer to the gut wall, notably the rheology and permeability of digesta. The second section examines the effects of the alimentary, mechanical and biophysical processes on mixing and mass transfer. Included is a comprehensive review of the effects of the various types of contractile activity in the gut wall in securing efficient mixing and onflow of digesta through the various segments of the gut. The section also examines what is known of the actions of the mucinous and cellular components of the gut wall in lubricating the passage of digesta and in limiting the permeation and absorption of nutrients, pharmaceuticals and microbial products. The section concludes with a review of the effects of the various physical and morphological components of the gut wall that constitute the ‘unstirred water layer’ on the process of absorption. The authors are leaders in their field and have extensively researched the literature. The work cites over 1500 references including those pertaining to the latest developments. Front Matter....Pages 1-1 Front Matter....Pages 9-10 Introduction....Pages 1-7 Front Matter....Pages 9-10 The Microstructure and Digestion of Particles....Pages 11-29 Physical Aspects of the Digestion of Carbohydrate Particles....Pages 31-46 Physical Aspects of the Digestion of Protein Particles....Pages 47-61 Colloidal Dynamics and Lipid Digestive Efficiency....Pages 63-90 The Physical Characteristics of Digesta....Pages 91-117 Front Matter....Pages 119-120 Contractile Activity and Control of the Physical Process of Digestion Within a Gut Segment....Pages 121-153 Local Motility, Flow and Mixing in Tubular Segments of the Gut....Pages 155-188 Local Motility and Flow in Segments that Exhibit Volume Retention....Pages 189-219 Flow, Mixing and Absorption at the Mucosa....Pages 221-274 Back Matter....Pages 270-270