The Stomach. Its function is to: (i) massage and mix the food with stomach acids and (ii) start the breakdown of proteins.
The Liver. Its function is to: (i) manufacture bile and secrete it into the duodenum which helps break down the fatty acids, (ii) remove toxins from the blood such as drugs, chemicals (eg food additives, insecticides), (iii) process alcohols (natural food alcohols from sugars as well as intoxicants).
The Gall Bladder. Its function is to: store bile and release it into the duodenum when needed.
The Pancreas. Its function is to: (i) secrete enzymes for digestion, (ii) manage insulin to regulate blood sugar levels.
Figure 57 - Anatomy of the Digestive System
For our body machine to work properly, all the right substances must be present both in our food intake and in our internal body chemistry. Some of these must be taken in because the body can't make them, and others are made within us with help from our dietary intake. The basic food substances are as follows.
Carbohydrates are slow release energy foods which break down into sugars of various types such as starch, glycogen, sucrose, lactose, fructose. These are not to be confused with "Sugar" which is a highly refined end-product sucrose and only gives a quick energy hit. They also produce heat which the body needs for all its functions.
Proteins are the building blocks for all body cells. They repair old tissues and help resistance to disease. They help produce other substances such as hormones and enzymes.
Fats store body energy, insulate against cold, provide protective layers against damage.
Vitamins are necessary nutrients required in trace amounts. Some come from food and others are synthesised in the body. There are 2 types, fat soluble (A, D, E, K) and water soluble (B group and C). They act as catalysts to other chemical reactions.
Salts and Minerals are also needed in trace amounts. They work in conjunction with other major chemicals and help balance body pH (that is acidity and alkalinity).
Water represents 60 - 70% of body weight. The correct balance of water consumed within a meal and at other times during the day, is very important for digestion as well as all other metabolic processes.
Physiologically, the total process of digestion and assimilation involves hundreds of other more complicated, technically intricate, chemical reactions and conversions; hormonal stimuli; nervous impulses; glandular secretions, muscular interactions; all of which are not necessary to know about for general good health. But in your own time, making a more detailed study of all this will serve to awaken you to the wonders of our human existence.