The energy required for all the processes and activities that take place in our bodies is derived from the foods we ingest. The digestive system allows us to utilize food from such diverse sources as meat from an animal and the roots of a plant, and utilize them as an energy source. Whether it is the ability to coordinate the chewing of the food without injuring our tongue and lips or the propulsion of the food from the stomach into the duodenum while releasing the appropriate enzymes, our digestive system allows us to manage the process without much thought and often while performing other tasks.
1. Digestion is important for breaking down food into nutrients, which the body uses for energy, growth, and cell repair.2. Digestion works by moving food through the gastrointestinal (GI) tract.3. Digestion begins in the mouth with chewing and ends in the small intestine.4. Molecules of food to break down into smaller molecules. The body then absorbs these smaller molecules through the walls of the small intestine into the bloodstream, which delivers them to the rest of the body.5. Waste products of digestion pass through the large intestine and out of the body as a solid matter called stool.6. The small intestine absorbs most digested food molecules, as well as water and minerals, and passes them on to other parts of the body for storage or further chemical change. Hormone and nerve regulators control the digestive process.
1. Stomach: With age, the stomach lining’s capacity to resist damage decreases, which in turn may increase the risk of peptic ulcer disease, especially in people who use aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs). Also with age, the stomach cannot accommodate as much food (because of decreased elasticity), and the rate at which the stomach empties food into the small intestine decreases. However, these changes typically do not cause any noticeable symptoms. Ageing has little effect on the secretion of stomach juices such as acid and pepsin, but conditions that decrease acid secretion, such as atrophic gastric, become more common.
2. Small intestine: Aging has only minor effects on the structure of the small intestine, so movement of contents through the small intestine and absorption of most nutrients do not change much. However, lactase levels decrease, leading to intolerance of dairy products by many older adults (lactose intolerance ). Excessive growth of certain bacteria (bacteria, overgrowth syndrome ) becomes more common with age and can lead to pain, bloating, and weight loss. Bacterial overgrowth may also lead to decreased absorption of certain nutrients, such as vitamin B12, iron, and calcium.
3. Large intestine and rectum: The large intestine does not undergo much change with age. The rectum does enlarge somewhat. Constipation becomes more common (see constipations in adult : essential for older people ), which is caused by many factors:
1. A slight slowing in the movement of contents through the large intestine.2. A modest decrease in the contractions of the rectum when filled with stool.3. More frequent use of drugs that can cause constipation. Often less exercise or physical activity. 4.Viral or bacterial infection: and parasites. Bacteria, viruses and parasites can get into the digestive system by means of contact with contaminated surfaces, or contact with infected stools and then ingesting the germs or from eating infected food or drinking infected water.
5.Structural causes: A structural abnormality in the digestive system (such as the pouches that develop in the intestines of someone with diverticulitis) can hamper the working of the digestive system. An ulcer in the stomach lining or the intestines would be another example, as would be a cancerous tumor.6. Systemic diseases: Many systemic diseases affect our gastrointestinal systems, such as autoimmune diseases (i.e. scleroderma that affects the motility of the gut), heart failure (the chronic congestion can cause liver cirrhosis), genetic diseases, HIV and diabetes.