Digestion
The gastrointestinal tract and the process of digestion are illustrated in. Digestion is the gastrointestinal process of breaking down food and absorbing its constituents into the body. In order the appreciate the basics of digestion, it is useful to consider the body without its protuberance, as simple living tube with a hole at each end. To supply itself with energy and other nutrients, the tube puts food in to one of it to holes – the one with teeth - and passes the food along its internal canal so that the food can be broken down and partially absorbed from the canal in to the body. The leftovers are jettisoned from the other end. Although this is not a particularly appetizing description of eating, it does serve to illustrate that, strictly speaking, food has not been consumed until it has been digested.