The appendix is a finger-shaped pouch attached to the cecum. The cecum is the first part of the large intestine. The colon is next. The rectum is the end of the large intestine. Bacteria in your GI tract, also called gut flora or microbiome, help with digestion. Parts of your nervous and circulatory systems also help. Working together, nerves, hormones , bacteria, blood, and the organs of your digestive system digest the foods and liquids you eat or drink each day.
Digestion is important because your body needs nutrients from food and drink to work properly and stay healthy. Proteins , fats , carbohydrates , vitamins , minerals , and water are nutrients. Your digestive system breaks nutrients into parts small enough for your body to absorb and use for energy, growth, and cell repair. MyPlate offers ideas and tips to help you meet your individual health needs.
Each part of your digestive system helps to move food and liquid through your GI tract, break food and liquid into smaller parts, or both. Once foods are broken into small enough parts, your body can absorb and move the nutrients to where they are needed. Your large intestine absorbs water, and the waste products of digestion become stool. Nerves and hormones help control the digestive process. Food moves through your GI tract by a process called peristalsis. The large, hollow organs of your GI tract contain a layer of muscle that enables their walls to move.
The movement pushes food and liquid through your GI tract and mixes the contents within each organ. The muscle behind the food contracts and squeezes the food forward, while the muscle in front of the food relaxes to allow the food to move. Food starts to move through your GI tract when you eat. When you swallow, your tongue pushes the food into your throat. A small flap of tissue, called the epiglottis, folds over your windpipe to prevent choking and the food passes into your esophagus.
Once you begin swallowing, the process becomes automatic. Your brain signals the muscles of the esophagus and peristalsis begins. Lower esophageal sphincter. Electrolyte balance is regulated by hormones, generally with the kidneys flushing out excess levels.
In humans, electrolyte homeostasis is regulated by hormones such as the antidiuretic, aldosterone, and parathyroid hormones. Serious electrolyte disturbances, such as dehydration and over-hydration, may lead to cardiac and neurological complications that, unless they are rapidly resolved, will result in a medical emergency. Water and minerals are reabsorbed back into the blood in the colon large intestine where the pH is slightly acidic—about 5.
Privacy Policy. Skip to main content. Digestive System. Search for:. Absorption in the Small Intestine The absorption of nutrients occurs partially by diffusion through the wall of the small intestine. Learning Objectives Describe the role played by the small intestine in the absorption of nutrients. Key Takeaways Key Points Digested food is able to pass into the blood vessels in the wall of the small intestine through the process of diffusion.
The inner wall, or mucosa, of the small intestine is covered in wrinkles or folds called plicae circulares that project microscopic finger-like pieces of tissue called villi, which in turn have finger-like projections known as microvilli. Each villus transports nutrients to a network of capillaries and fine lymphatic vessels called lacteals close to its surface. Key Terms villi : Tiny, finger-like projections that protrude from the epithelial lining of the intestinal wall.
Examples Examples of nutrients absorbed by the small intestine include carbohydrates, lipids, proteins, iron, vitamins, and water. Absorption of Monosaccharides, Amino Acids, Dipeptides, Tripeptides, Lipids, Electrolytes, Vitamins, and Water Glucose, amino acids, fats, and vitamins are absorbed in the small intestine via the action of hormones and electrolytes. A person normally isn't aware of the movements of the esophagus, stomach, and intestine that take place as food passes through the digestive tract.
At the end of the esophagus, a muscular ring or valve called a sphincter pronounced: SFINK-ter allows food to enter the stomach and then squeezes shut to keep food or fluid from flowing back up into the esophagus.
The stomach muscles churn and mix the food with digestive juices that have acids and enzymes, breaking it into much smaller, digestible pieces. An acidic environment is needed for the digestion that takes place in the stomach.
By the time food is ready to leave the stomach, it has been processed into a thick liquid called chyme pronounced: kime. A walnut-sized muscular valve at the outlet of the stomach called the pylorus pronounced: pie-LOR-us keeps chyme in the stomach until it reaches the right consistency to pass into the small intestine. Chyme is then squirted down into the small intestine, where digestion of food continues so the body can absorb the nutrients into the bloodstream.
The inner wall of the small intestine is covered with millions of microscopic, finger-like projections called villi pronounced: VIH-lie. The villi are the vehicles through which nutrients can be absorbed into the blood. The blood then brings these nutrients to the rest of the body. The liver under the ribcage in the right upper part of the abdomen , the gallbladder hidden just below the liver , and the pancreas beneath the stomach are not part of the alimentary canal, but these organs are essential to digestion.
The liver makes bile , which helps the body absorb fat. Bile is stored in the gallbladder until it is needed. Fat molecules are a rich source of energy for the body. The first step in digestion of a fat such as butter is to dissolve it into the water content of the intestinal cavity.
The bile acids produced by the liver act as natural detergents to dissolve fat in water and allow the enzymes to break the large fat molecules into smaller molecules, some of which are fatty acids and cholesterol. The bile acids combine with the fatty acids and cholesterol and help these molecules to move into the cells of the mucosa.
In these cells, the small molecules are formed back into large molecules, most of which pass into vessels called lymphatics near the intestine. These small vessels carry the reformed fat to the veins of the chest, and the blood carries the fat to storage depots in different parts of the body.
The large, hollow organs of the digestive system contain muscle that enables their walls to move. The movement of organ walls can propel food and liquid and also can mix the contents within each organ. Typical movement of the esophagus, stomach, and intestine is called peristalsis. The action of peristalsis looks like an ocean wave moving through the muscle. The muscle of the organ produces a narrowing and then propels the narrowed portion slowly down the length of the organ.
These waves of narrowing push the food and fluid in front of them through each hollow organ. Most of the material absorbed from the cavity of the small intestine is water in which salt is dissolved. The salt and water come from the food and liquid we swallow and the juices secreted by the many digestive glands. In a healthy adult, more than a gallon of water containing over an ounce of salt is absorbed from the intestine every 24 hours.
A fascinating feature of the digestive system is that it contains its own regulators. The major hormones that control the functions of the digestive system are produced and released by cells in the mucosa of the stomach and small intestine.
These hormones are released into the blood of the digestive tract, travel back to the heart and through the arteries , and return to the digestive system, where they stimulate digestive juices and cause organ movement. The hormones that control digestion are gastrin, secretin, and cholecystokinin CCK :.
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