43. Introduction to the gastrointestinal system
43. Introduction to the gastrointestinal system
- 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 describes the gross anatomical organization of the gastrointestinal system, the internal structure of the gut wall, and its blood supply. It provides an overview of the nervous and hormonal mechanisms that regulate the motility and secretory activity of the gut. It also presents a detailed examination of the structure and functions of the mouth and oesophagus, the stomach, and the small and large intestine, together with the digestive functions of the pancreas. The chapter outlines key aspects of nutrition and energy balance, noting how food is required by the body both for the production of energy and for the growth and repair of tissues. Each day an average adult consumes around 1 kg of solid food and 1-2 litres of fluid. The majority of this material is in a form that first must be broken down into simple molecules.
