Function of the Digestive System
When the chyme is fully digested, it is absorbed into the blood. These include the various cells of the gastric glands, taste cells , pancreatic duct cells , enterocytes and microfold cells. The large intestine is a long, thick tube about 2. These folds together with villi serve to increase the surface area of the jejunum enabling an increased absorption of digested sugars, amino acids and fatty acids into the bloodstream. The organs known as the accessory digestive glands are the liver , gall bladder and pancreas. The parietal cells in the fundus of the stomach, produce a glycoprotein called intrinsic factor which is essential for the absorption of vitamin B When you eat, your gallbladder squeezes bile through the bile ducts into your small intestine.
What is the digestive system?
Instead, muscles in the walls of the esophagus move in a wavy way to slowly squeeze the food through the esophagus. This takes about 2 or 3 seconds. Your stomach, which is attached to the end of the esophagus, is a stretchy sack shaped like the letter J. It has three important jobs:. The stomach is like a mixer, churning and mashing together all the small balls of food that came down the esophagus into smaller and smaller pieces.
It does this with help from the strong muscles in the walls of the stomach and gastric say: GAS-trik juices that also come from the stomach's walls. In addition to breaking down food, gastric juices also help kill bacteria that might be in the eaten food. The small intestine say: If you stretched out an adult's small intestine, it would be about 22 feet long 6.
The small intestine breaks down the food mixture even more so your body can absorb all the vitamins, minerals, proteins, carbohydrates , and fats. PAN-kree-uss , liver, and gallbladder. Those organs send different juices to the first part of the small intestine. These juices help to digest food and allow the body to absorb nutrients.
The pancreas makes juices that help the body digest fats and protein. A juice from the liver called bile helps to absorb fats into the bloodstream. And the gallbladder serves as a warehouse for bile, storing it until the body needs it.
Your food may spend as long as 4 hours in the small intestine and will become a very thin, watery mixture. It's time well spent because, at the end of the journey, the nutrients from your pizza, orange, and milk can pass from the intestine into the blood. Once in the blood, your body is closer to benefiting from the complex carbohydrates in the pizza crust, the vitamin C in your orange, the protein in the chicken, and the calcium in your milk.
Next stop for these nutrients: And the leftover waste — parts of the food that your body can't use — goes on to the large intestine. The nutrient-rich blood comes directly to the liver for processing. The liver filters out harmful substances or wastes, turning some of the waste into more bile.
The liver even helps figure out how many nutrients will go to the rest of the body, and how many will stay behind in storage. For example, the liver stores certain vitamins and a type of sugar your body uses for energy. At 3 or 4 inches around about 7 to 10 centimeters , the large intestine is fatter than the small intestine and it's almost the last stop on the digestive tract. Like the small intestine, it is packed into the body, and would measure 5 feet about 1.
The large intestine has a tiny tube with a closed end coming off it called the appendix say: It's part of the digestive tract, but it doesn't seem to do anything, though it can cause big problems because it sometimes gets infected and needs to be removed.
Like we mentioned, after most of the nutrients are removed from the food mixture there is waste left over — stuff your body can't use. This stuff needs to be passed out of the body. Can you guess where it ends up? Well, here's a hint: It goes out with a flush. Before it goes, it passes through the part of the large intestine called the colon say: The stomach also contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in the mouth.
It is located just inferior to the stomach and takes up most of the space in the abdominal cavity. The entire small intestine is coiled like a hose and the inside surface is full of many ridges and folds. These folds are used to maximize the digestion of food and absorption of nutrients. The liver is a roughly triangular accessory organ of the digestive system located to the right of the stomach, just inferior to the diaphragm and superior to the small intestine.
The liver weighs about 3 pounds and is the second largest organ in the body. The liver has many different functions in the body, but the main function of the liver in digestion is the production of bile and its secretion into the small intestine.
The gallbladder is a small, pear-shaped organ located just posterior to the liver. The gallbladder is used to store and recycle excess bile from the small intestine so that it can be reused for the digestion of subsequent meals.
The pancreas is a large gland located just inferior and posterior to the stomach. The pancreas secretes digestive enzymes into the small intestine to complete the chemical digestion of foods. The large intestine is a long, thick tube about 2. It is located just inferior to the stomach and wraps around the superior and lateral border of the small intestine.
The large intestine absorbs water and contains many symbiotic bacteria that aid in the breaking down of wastes to extract some small amounts of nutrients. Feces in the large intestine exit the body through the anal canal.
The digestive system is responsible for taking whole foods and turning them into energy and nutrients to allow the body to function, grow, and repair itself. The six primary processes of the digestive system include:. The first function of the digestive system is ingestion, or the intake of food. The mouth is responsible for this function, as it is the orifice through which all food enters the body.
The mouth and stomach are also responsible for the storage of food as it is waiting to be digested. This storage capacity allows the body to eat only a few times each day and to ingest more food than it can process at one time.
In the course of a day, the digestive system secretes around 7 liters of fluids. These fluids include saliva, mucus, hydrochloric acid, enzymes, and bile. Saliva moistens dry food and contains salivary amylase, a digestive enzyme that begins the digestion of carbohydrates. Mucus serves as a protective barrier and lubricant inside of the GI tract. Hydrochloric acid helps to digest food chemically and protects the body by killing bacteria present in our food. Enzymes are like tiny biochemical machines that disassemble large macromolecules like proteins, carbohydrates, and lipids into their smaller components.
Finally, bile is used to emulsify large masses of lipids into tiny globules for easy digestion. Digestion is the process of turning large pieces of food into its component chemicals. Mechanical digestion is the physical breakdown of large pieces of food into smaller pieces. This mode of digestion begins with the chewing of food by the teeth and is continued through the muscular mixing of food by the stomach and intestines.
Bile produced by the liver is also used to mechanically break fats into smaller globules. While food is being mechanically digested it is also being chemically digested as larger and more complex molecules are being broken down into smaller molecules that are easier to absorb.
Chemical digestion begins in the mouth with salivary amylase in saliva splitting complex carbohydrates into simple carbohydrates. The enzymes and acid in the stomach continue chemical digestion, but the bulk of chemical digestion takes place in the small intestine thanks to the action of the pancreas.