Digestive System Part I

Digestion is a breakdown of large food components to smaller ones. It is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. When food enters the mouth, digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, contains salivary amylase, an enzyme which starts the digestion of starch in the food. After undergoing mastication and starch digestion, the food will then travel down the esophagus and into the stomach. Gastric juices in the stomach then start to digest the proteins. Gastric juices contain chemicals that may damage the stomach wall, so mucus is secreted by the stomach, providing a slimy layer that shields against the damaging effects of the chemicals. At the same time, a mechanical mixing occurs when waves of muscular contractions along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. After some time (typically 1-2 hours in humans) the resulting thick liquid enters the duodenum where it will mix with digestive enzymes from the pancreas, and passes through the small intestine, in which digestion continues. When the thick liquid is fully digested, it is absorbed into the blood. 95% of absorption of nutrients occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon (large intestine). Waste material is eliminated through the rectum during defecation.

The stomach

The stomach is a vital organ, digesting food non-stop. Nevertheless, we tend to be unkind to our stomachs by our irregular eating habits, overeating and drinking too much. These unhealthy habits pose a risk of hurting the stomach, causing physical fatigue and making us susceptible to various illnesses.

It’s worth noting that the stomach and other digestive organs can also be affected by mental stress, leading to loss of appetite which in turn can cause the bleeding of the stomach linings and stomach ulcer. Thus even with a busy modern life, we should not ignore our stomachs – watch our diet, and especially keep our mealtimes regular.

Mechanism of the stomach

The main function of this muscular, hollow organ is to digest masses of food from the mouth. During digestion, proteins, carbohydrates, fat, glucose and fatty acids are formed into amino acids and absorbed. Gastric acid is also produced to help digest proteins. However, overeating, drinking too much as well as stress can overwork the stomach, with the gastric system scratching the stomach walls. When that happens, the whole digestive system is in disarray and your body will weaken.

Stomach problems


This is when food becomes hard to digest because of overeating or overdrinking. Bloating feels like the food has been stored in the stomach for a long time. Taking gastrointestinal drugs with ingredients that promote digestion, is recommended.

Acute gastritis (stomach pain)

This is a pain in the pit (bottom) of the stomach, followed sometimes by vomitting. Caused by too much eating and drinking, this is a common of stomach problems. It may also be caused by the side effects of certain medicines such as antibiotics and cold medicines. Treatment is by taking digestive medicine for the purpose of pain relief and protection of the gastric mucosa, but see a doctor if the condition worsens.

With bloatedness and overeating, the symptoms can disappear after a couple of days if you have enough rest and take appropriate medication. Also avoid certain foods that can cause further irritations to your digestive system. Salty and spicy foods and alcohol and tobacco may cause over-secretion of gastric acid and harm your stomach linings.


As mentioned earlier, stress affects the stomach’s normal function. Many people tend to smoke, drink or eat more when stressed, but these will cause over-exertion of the stomach and stomach linings. Relaxing and de-stressing does wonders for your mind and stomach too.

Loss of appetite

Anorexia is the decreased sensation of appetite. Many possible causes exist for anorexia, some may be harmless, while others indicate a serious condition or pose a significant risk. Anorexia is more likely to affect persons suffering from conditions such as a common cold, or a disease which affects the stomach, liver, kidneys or heart. Loss of appetite can also occur with the effects of nicotine in drugs and tobacco, while lack of sleep, fatigue and psychological conditions such as stress and worrying also play an important role. Appetite is controlled not just by the digestive system, but by the brain as well, such as triggering the desire to eat by the smell of food. Gradual loss of appetite can be caused by stress, overworking, overeating, excessive drinking, fatigue or when your bodyclock or physiological balance are disrupted. For many young women, psychological factors such as depression, insomnia, menstruation or irregular weight loss and gain also can cause anorexia.

Sudden loss of appetite

A sudden loss of appetite is one of the symptoms of acute gastritis. If accompanied by nausea, diarrhoea and fever it could be acute gastroenteritis viral. Missed periods and a sudden loss of appetite could also be due to pregnancy.

Lack of food means a lack of nutrition not just for the for the body, but for the mind too. In situations such as these, those with anorexia should take rest and relax the mind.

One should also try to lead a regular life, as far as eating and resting habits go. Irregular meals, lates nights all contribute greatly to the welfare of your digestive system. Vitamins and diet supplements are also helpful, as well as taking enough fluids, and antacids and other digestive medication also help relieve stomach discomfort. It’s important to take the correct gastrointestinal drug as there are types that aid digestion and encourage the secretion of gastric acid; and the types that supress it.


Gastric pain and heartburn

Gastritis symptoms are most common among gastrointestinal diseases, and involve symptoms like stomach pain, heartburn, nausea, bloating, and loss of appetite. Some of the main causes of heartburn and stomach pain when there is excessive secretion of gastric acid are overeating, alcohol and stress.

The stomach may be a muscular organ but it works very hard, non-stop. Overeating, too much alcohol, stress, etc… the rhythm of gastric acid can get upset by all these. As a result, this acid is secreted in excess, hurting or even damaging the mucous membrane of the stomach, causing heartburn. As always, consult a doctor immediately if symptoms persist or get worse.


Also known as pyrosis, cardialgia, or acid indigestion heartburn is a burning sensation felt in the chest, just behind the breastbone. The pain often rises in the chest and may spread to the neck, throat, or angle of the jaw. Heartburn is usually associated with regurgitation of gastric acid. Symptoms of heartburn are sometimes confused with the pain that is a symptom of an acute myocardial infarction (heart attack). Some people may get heartburn with the consumption of certain foods like fried food, chocolates, coffee, carbonated drinks and alcohol.

Gastric pain (acute gastritis)

Main causes of gastric pains are overeating and drinking of alcohol, as they cause the over-secretion of gastric acid, hurting and roughening the stomach walls in the process. You can also get gastric pains as a side effect of medications such as antibiotics and cold medicines; allergic reactions; or food poisoning. Serious gastric pains can also be accompanied by vomitting.

Proper care for gastric pain is to rest your stomach as much as possible. This may include skipping 1 or 2 meals if possible, and drinking warm water or sports drinks. A soft diet of tofu or porridge will also help your stomach recover gradually.

Upon the onset of early symptoms of gastric pains, taking appropriate gastrointestinal medicines will help early recovery. For heartburn, you can take certain antacids and H2 blockers. Some medication are formulated with sucralfate which binds to the stomach lining.

Even for someone who is healthy, heartburn can occur due to irregular meals or eating habits. Overeating, eating too quickly, spicy and oily food, smoking and alcohol and stress are typical causes of gastric pains.


The frequency of bowel movement may vary from person to person, however when satisfactory bowel movement is not achieved, it is considered to be constipation. Even if there’s bowel movement every day, the amount may be insufficient, and there is a feeling that you have not been able to completely empty your bowels. It is important to take care of the symptoms because you wouldn’t want it to becme a chronic ailment. Many people suffer from functional constipation; this is often tension and stress related, as these can affect the workings of the intestine and its secretions. To improve the situation, it is important to clear bowels regularly and proper diet and exercise can help the intestine work more efficiently and reestablish natural daily rhythms. There is however, also constipation caused by physical lesions and cancer of the bowel. Should you detect blood in your stools, be sure to consult a doctor immediately.


How constipation occurs

Our body has two systems: the colorectal system and the stomach/colon system, they act together to bring about bowel movement. The colorectal system is responsible for communicating with the brain and based on this we get ready to pass stools. When this message is received, colon movement excretes the stools. Even before that, when food enters the stomach, the stomach/colon system starts the reflexive contraction of the colon in preparation. Constipation is caused when these systems get affected by stress and irregular life habits. In addition, lack of dietary fibre and sufficient water can also lead to probems in emptying bowels and cause constipation.

Acute constipation

If there are disruptions to one’s normal pattern of life, such as hospitalisation, a lot of travel, major changes, it may have a psychological effect and lead to constipation. This is a disorder of the autonomic nervous system because of changes in the environment and usually not a cause for great concern. But if this is accompanied with severe vomiting, abdominal pain, etc., please consult a physician immediately.

Chronic constipation

This may be caused by changes in one’s life and environment. It is often found among postpartum women, the elderly, and people with a lower food intake. The intestinal movement of the large intestine may be weakened and because of higher moisture absorption by the system, stools are often hard.

Constipation caused because of withholding bowel movement

This is a pattern common in people who are prone to suppressing the urge to have a bowel movement because of discomfort of some sort including hemorrhoids. The urge to defecate may be dulled, leading to accumulation of bowel matter in the rectum and chronic constipation.

Constipation due to Irritable Bowel Syndrime

This can be very sensitive to the slightest stress. Intestinal convulsions interfere with the smooth flow of stools along the system. Stools are often hard and pellet like.

Care when having constipation

Disruption in the normal rhythm of life can lead to constipation. The defecation reflex will most likely occur in the morning, it is important to go with the natural rhythm of the bowel system. Do take your breakfast and make it a point to clear your bowels after meals. No matter how busy you may be, do not hold back bowel movements.