The Digestive System:
The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus, and is responsible for eating, digestion and excretion. Digestion is the process by which food and drink are broken down into their smallest parts, so that the body can use them to build and nourish cells and provide energy.
When we eat, most of the foods are not in a form that the body can use as nourishment. Our food and drink must be changed into smaller molecules before they can be absorbed into the blood and carried to cells throughout the body. The digestive system contains a number of organs responsible for changing food chemically in order to enable their absorption by body tissues. The process involves breaking food down into simple soluble substances that are absorbable. Ask yourself each time you eat: “What nutritional value does this food have for my body?”
The series of structures that transform the foods we eat into substances that can be used by the body for growth, repair and energy include the mouth, salivary glands, oesophogus, stomach, liver, gall bladder, pancreas, small and large intestines and anus. After digestion, the intestinal walls absorb the nutrient molecules, which are then circulated around the body. The food that does not get digested becomes waste matter and is excreted as faeces.
Digestion incorporates both physical and chemical processes. The physical processes include chewing to reduce food to small particles, the churning action of the stomach and intestinal peristaltic action (rippling muscle contractions that push food through the digestive tract). The three chemical reactions that take place are the conversion of carbohydrates into simple sugars such as glucose; the breaking down of protein into amino acids; and the conversion of fats into fatty acids. These processes are accomplished by specific enzymes.
A healthy digestive system is the cornerstone of good health. If the digestive system is not functioning well, it can lead to vitamin and nutritional deficiencies, because the cells and other parts of the body cannot receive the energy they need in order to work properly. Deficiencies can manifest in various ways, such as a poor immune system, infertility, depression or the onset of various diseases.