44. The gastrointestinal tract
44. The gastrointestinal tract
- Gillian Pocock, Gillian PocockSenior Lecturer in Clinical Science, Canterbury Christ Church University, Canterbury, UK
- Christopher D. RichardsChristopher D. RichardsEmeritus Professor of Experimental Physiology, Division of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University College London, London, UK
- and David A. RichardsDavid A. RichardsAssociate Professor, Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine, USA
Abstract
This chapter discusses the principal function of the gastrointestinal (GI) system. It highlights how the GI system converts foods eaten into simple molecules that can be absorbed into the bloodstream and utilized by the cells of the body for energy and to build and repair body tissues. The structures that carry out these tasks may be divided into those that form the alimentary canal itself and the accessory organs that contribute to mechanical digestion or to chemical digestion through the secretion of various fluids and enzymes. The chapter provides a detailed explanation of the roles played by the different parts of the GI system in the processes of ingestion, digestion, absorption, and elimination of indigestible remains. It covers the complex nervous and hormonal mechanisms that regulate motility and secretory activity.
