Composition of the digestive system and common diseases

The digestive system is an important system of the human body. It is a set of organ systems responsible for processing food, extracting and absorbing nutrients from it, and eliminating waste. It includes a series of interconnected organs, starting from the mouth, passing through the esophagus, stomach, small intestine, large intestine, and finally reaching the rectum and anus. In addition, the digestive system also includes several organs that assist digestion, such as the liver, pancreas, and gallbladder, which secrete important digestive enzymes and substances to help break down food and are essential for maintaining good health.

1. System structure and functions

1. Oral cavity. This includes the teeth, tongue, and salivary glands, which break down food mechanically and chemically through the enzyme amylase in saliva.

2. Esophagus. A muscular tube about 25 cm long that moves food through peristalsis.

3. Stomach. A large muscular pouch that uses muscle contractions to mix food into a paste for storage and secretes gastric acid and digestive enzymes (such as pepsin) to digest food, primarily protein.

4. Small intestine. It consists of the duodenum, jejunum and ileum. The inner wall of the small intestine is covered with villi and microvilli, which increase the absorption area and is the main absorption area for nutrients.

5. Large intestine. It includes the cecum (with appendix), colon (divided into ascending colon, transverse colon, descending colon and sigmoid colon) and rectum. Its main function is to absorb water and electrolytes and form and store feces.

6. Liver. The largest internal organ in the human body, located in the upper right part of the abdomen, produces bile that is transported to the small intestine through the bile duct to help digest fat, metabolize, and store nutrients.

7. Pancreas. Located behind the stomach, it is a long gland that transports digestive enzymes to the small intestine through the pancreatic duct to help digest proteins, fats and carbohydrates.

8. Rectum and anus. The rectum is the last part of the large intestine, and the anus is the exit of the digestive tract. They can store and excrete unabsorbed waste from the body.

2. Common digestive system diseases

The digestive system is very complex and prone to many diseases. Here are some common digestive system diseases.

1. Gastroesophageal reflux disease (GERD). This is a common disease in which stomach acid or other stomach contents flow back into the esophagus, causing symptoms such as epigastric pain (burning sensation behind the breastbone), difficulty swallowing, and acid regurgitation. Long-term GERD may lead to esophagitis or esophageal stricture.

2. Gastric ulcer and duodenal ulcer. These ulcers are localized injuries to the digestive tract mucosa, usually caused by Helicobacter pylori infection or long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). The main symptoms include abdominal pain, indigestion, and postprandial discomfort.

3. Irritable bowel syndrome (IBS). IBS is a functional gastrointestinal disease with main symptoms including abdominal pain, bloating and changes in bowel habits (diarrhea or constipation). Its exact cause is still unclear, but it may be related to intestinal sensitivity, intestinal motility dysfunction and psychological factors.

4. Inflammatory bowel disease (IBD). This includes Crohn’s disease and ulcerative colitis. These diseases are characterized by persistent inflammation in the intestines that may cause abdominal pain, persistent diarrhea, weight loss, and fatigue. Inflammation may cause intestinal damage and even increase the risk of colon cancer.

5. Cholelithiasis. Gallstones are solid particles formed in the gallbladder or bile duct, mainly composed of cholesterol or bile pigment. Gallstones may cause cholecystitis, cholangitis or pancreatitis.

6. Pancreatitis. Pancreatitis is an inflammation of the pancreas, often caused by gallstones, alcoholism or other medical conditions. Symptoms include severe abdominal pain, nausea and vomiting. Severe pancreatitis can be life-threatening.

7. Intestinal obstruction. Intestinal obstruction is a condition in which food and fluids cannot pass normally because the intestines are blocked or compressed. Symptoms include severe abdominal pain, vomiting, bloating, and constipation. Intestinal obstruction may be caused by intestinal adhesions, tumors, or inflammation.

8. Colon cancer. Colon cancer is one of the more common types of cancer in the digestive system. There may be no obvious symptoms in the early stages, but as the disease progresses, bloody stools, persistent abdominal pain, weight loss, and unexplained fatigue may occur. Regular colonoscopy is an important means of preventing and early detection of colon cancer.

9. Liver disease. This includes hepatitis, cirrhosis, and liver cancer. Liver disease may be caused by viral infection (such as hepatitis B or C virus), alcohol abuse, obesity (non-alcoholic fatty liver disease), or other genetic factors.

10. Gastric cancer. Gastric cancer often has no obvious symptoms in the early stages, but in the late stages, indigestion, abdominal pain, loss of appetite, and weight loss may occur. Risk factors for gastric cancer include long-term Helicobacter pylori infection, smoking, high-salt diet, and family history.

3. The Importance of the Digestive System

The digestive system is a vital part of the human body. It is not only responsible for the digestion of food and the absorption of nutrients, but also affects the overall health of the human body and the prevention of diseases. Maintaining the health of the digestive system not only depends on the advancement of medical technology, but also requires each of us to adopt an active lifestyle in our daily lives, such as a reasonable diet, moderate exercise, and effective stress management.

At the same time, regular physical examinations and timely medical treatment are also the key to preventing and early diagnosis of digestive system diseases.

In short, through the help of technology and personal efforts, we can better understand and manage the health of the digestive system, thereby improving the quality of life and health level.

Author: Chen Xiangyi, Department of Gastroenterology, Pubei County People's Hospital, Qinzhou City