Gateway To Your Wealth & A Healthy Life!: THE DIGESTIVE SYSTEM

THE DIGESTIVE SYSTEM
Our digestive system is like a “compact, self-renewing conveyor belt”! It produces body tissues and energy out of a dazzling diversity of materials from rice to broccoli!
Reference from ABC’s of The Human Body (Readers Digest)

The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. Inside this tube is a lining called mucosa. In the mouth, stomach and small intestine, the mucosa contains tiny glands that produce juices to help digest food.

Why is digestion important?
When we eat food such as bread, meat and vegetables, they are not in a form that the body can use as nourishment. Our food and drink must be broken down into small absorbable nutrients so that the body can use them to build and replace cells, and generate the energy to maintain life.

How is food digested?
Digestion involves the mixing of food, its movement through the digestive tract, and chemical breakdown of large molecules of food into smaller molecules. Digestion begins in the mouth when we chew and swallow and is completed in the small intestine. The chemical process varies somewhat for different kinds of food.

How does food move through the system?
The large, hollow organs of the digestive system contain muscles that enable their walls to propel food and liquid, and also mix the contents within each organ. This movement of contraction and relaxation is called ‘peristalsis’ which is much like a ball through a collapsed inner tube.

 The mouth is the first stop on a journey of some 30 feet (9.1 meters) through the digestive canal. Food is crushed by teeth, and with the help of the tongue, mixed with saliva and propelled to the back of mouth and into the esophagus. Once the swallowing begins, it becomes involuntary and proceeds under the control of the nerves.

 The food then enters the stomach. The stomach has three mechanical tasks.

First, the stomach must store the swallowed food and liquid. The stomach is expandable. When filled to capacity, the average stomach can hold about 2.5 pints (1/2 liters) of food.

The second job is to mix the food, liquid and digestive juice produced by the stomach. Gastric juices are an important element in the digestion in the stomach. The hydrochloric acid destroys bacteria in food, helps to soften protein foods and fosters the secretion and effectiveness of pepsin (one of the major ingredients in the gastric juice) that breaks proteins down into simpler chemical substances.

The third task is to empty its contents slowly into the small intestine.

 Several factors affect emptying of the stomach, including the nature of the food (mainly its fat and protein content) and the degree of muscle action of the emptying stomach and the next organ to receive the contents (the small intestine).

 The fragmentation of food that begins in the mouth is completed in the small intestine. As food enters the duodenum from the stomach, it stimulates 4 different organs to release the chemicals needed to finish digestion.

The small intestine secretes pours out mucus to protect the duodenum from damage by gastric acid. It also produces hormones that stimulate the liver, pancreas and gallbladder to release digestive substances.

Bile from the gallbladder and alkaline juice from the pancreas neutralize acid. Digestive enzymes, secreted by the pancreas and small intestine, break down food into simple components that the body can use. Carbohydrates are converted to glucose and protein to amino acids. Fat is also partially digested prior to absorption.

 Finally, all of the digested nutrients are absorbed through the intestinal wall. Very little of what you eat, go to waste. More than 95% of it is absorbed into the body to provide you with the fuel you need to live; the rest is eliminated through the large intestine, also called ‘bowel’.

Two major parts of the large intestine are the colon and the rectum. The chief function of the first half of the colon is the absorption of fluids; the second half is basically a storage vessel.

The food residues that reach the large intestine are of little use to the body. The large intestine’s job is to remove fluid from these residues and to solidify them.

Intestinal chyme is a liquid when it enters the colon. As it travels through the bowel, the fluid is gradually absorbed through the intestinal wall and recycled through the bloodstream. What is left is compacted into semisolid feces.

Of the material that you eliminate (the feces), roughly three-quarters is water. The rest generally consists of protein, inorganic matter, fat, undigested food roughage, plus dried remainders of digestive juices and cells shed by the intestine, and dead bacteria.