Q. After the food has spent its appointed time in the duodenum, what is the next step?

A. The food then passes to the small intestine. This is a long continuous tube that coils round and round, and fills the area which is commonly known as ‘the tummy’ or ‘gut’ in colloquial talk. It roughly fills the space between the lower part of the rib cage and the pelvic bones. It starts at the end of the duodenum and finally runs into the large bowel at a dilated area called the caecum.

I might add that ‘small’ refers to its width, not length. It is quite narrow, much like a hose. It has soft walls, and is very moveable. In fact, it slips and slides over itself in a remarkable manner. On the outside it is shiny and glistening, and slimy to the touch. This is important so that there will be no obstruction to the passage of food along its length.

Q. What happens in this part of the system?

A. Here is where digestion of the food takes place, and for this reason it is a vital part of the body. The first part or two fifths of the small bowel is called the jejunum — coming from the Latin word jejunus which means empty (ever felt empty when hungry!); the second part, roughly three fifths, is called the ileum, which comes from another Latin word ilia which means intestines.

By the time food reaches the small gut, it has been acted on by the acids and chemicals of the stomach and duodenum, so that it is now a strange thickish fluid. It has been broken down into its basic natural components. The inner lining of the small bowel consists of a huge number of undulating folds, and on these are located tens of millions of microscopic finger-like projections called villi. These also contain a copious blood supply.

Q. What do the villi do?

A. The villi contact the food, and actively absorb it into the blood system. Various parts of the bowel concentrate on different food components, for example starches are absorbed more readily in one section, fats and proteins in another, vitamins in another area. As the food is automatically carried along by natural waves of contraction called peristalsis, gradually the food components are sucked up by the ingenious villi.

Q. What happens to the food after it goes into the blood stream?

A. From here it is conveyed into larger vessels called the portal system. This travels to the liver, where much of the material is stored. Sugars are converted to glycogen and kept for later use, whilst a certain amount travels to the tissues for immediate use.

Ever notice how you suddenly seem to have more energy after a good meal? Some vitamins are used at once, whilst some are stored for later use.

Q. Where does the small intestine end, and what happens then?

A. The small gut ends in the lower right side of the abdominal cavity at the ileo-caecal junction, where there is a small valve.

Q. Isn’t that where the appendix is located?

A. True, as nearly anyone who has suffered appendicitis, and probably had an operation knows. Have a look at where the surgeon’s scar is. This is called McBurney’s point. The caecum is an enlarged part of the bowel, and projecting from this is a small, narrow organ a bit like a pencil, usually 5-10 cm in length, called the vermiform appendix — vermiform because it looks a bit like a worm! It is strange the way doctors name things and the reasons. Normally the appendix is hollow enabling food to enter and leave it freely. Occasionally the mouth becomes jammed, probably with little stones or worms, germs inside suddenly reproduce en masse and a serious condition called acute appendicitis may develop.

Q. Is this really a serious disease in today’s modern world?

A. Yes it is. Fortunately, most people are aware of the possibility and will quickly report pain around the navel, or in the R.I.F. (the right iliac fossa as the doctors say) and have the correct treatment. But some foolishly neglect it, or do not realise the importance of the symptoms. Even in this enlightened day and age, about sixty Australians die annually from appendicitis! It is an incredibly large figure, but shows little sign of lessening each year.

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