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Diagram of the Digestive System And an Explanation of its Working

Diagram of the Digestive System
Digestive system helps in breaking complex food into simpler forms. With the help of a diagram in this article, let us understand the function of this system, and the organs that constitute it. There is an unlabeled diagram in the end of the article for readers to practice labeling.
Debopriya Bose
Last Updated: Feb 24, 2018
We run, we work, we think, we talk. How do you think we do all of that? Yes, as far as thinking and reasoning is concerned, our mind does play a big role. However, biologically our body is an amalgamation of different human body systems, each of which has a specific role to play. There are seven major organ systems that make up the human body. They are the nervous system, respiratory system, circulatory system, musculoskeletal system, digestive system, excretory system, and the reproductive system. In this article, we concentrate on the digestive system. To aid our understanding of the function and the various organs that constitute it, this article carries a labeled diagram, along with an unlabeled one at the end for the readers to identify and mark different organs.
Digestive System Functions
Our body is like a complex machine. It needs fuel to run. This fuel is provided by the food that we eat. The nutrients- carbohydrates and fats provide us this energy. However, just as a machine suffers from wear and tear, the cells of our bodies also wear out. New cells are required to replace the old and dead cells. The raw material for this growth is provided by proteins. We are also susceptible to a number of diseases which our immune system generally fights. Minerals are the nutrients that strengthen our immunity. However, these nutrients need to be broken into simpler forms, that can be absorbed by our cells. This is where function of the digestive system begins. There are a number of glands like liver and pancreas (to name a few), that secrete enzymes into the various organs of the digestive system, that speed up the process of digestion. These enzymes, that are more specifically known as digestive enzymes, promote the process of breaking the complex nutrients into simpler forms. The digestive enzymes trigger the reactions that take place in the digestive organs. The enzymes are transported through blood and are absorbed by the cells. How does the digestive system work and what are the benefits of digestive enzymes? Find out below.
Organs and Their Functions
The diagram of the digestive system that is provided in the article will give one a better understanding of this organ system, as the food moves down from the mouth, through the esophagus to the stomach, small intestine and the large intestine, before it is excreted through the rectum and the anus. The table, given below, gives a consolidated information about the main organs and their functions.
digestive system
Mouth/Oral Cavity
Secretion ~ Salivary Amylase secreted by the 3 salivary glands - parotid, submandibular and sublingual.
Function ~ We chew food to break it down into smaller pieces. Thus, greater surface area is provided for the enzymes released by the salivary glands. This makes it easier to break down the carbohydrates present in the food.
Secretion ~ None
Function ~ The esophagus does not have any digestive role. It just helps push down the food from the mouth to the next organ, that is the stomach. This it does by the process of peristalsis.
Secretion ~ Gastric acid, pepsin (an enzyme), and various other digestive enzymes
Function ~ The muscles of the stomach churn the food and mix it with gastric juice and enzymes released by the stomach. The gastric juice maintains the acidic pH, so that food gets partly digested in the stomach. Pepsin breaks down proteins (into amino acids). The other enzymes, for example, gastric amylase and lipase, abd further breakdown carbohydrates and fats respectively.
Small Intestine
Secretion ~ Bile and pancreatic enzymes secreted by the pancreas enter the duodenum, other intestinal enzymes also act upon the chyme.
Function ~ It is in the small intestine that digestion is completed and all the nutrients (present in their simplest form) are absorbed by blood through the walls of the small intestine. Bile secreted by the pancreas emulsifies fat, so that it can be easily absorbed. The pancreatic and intestinal enzymes complete the final stage of digestion of proteins, fats, and carbohydrates.
Large Intestine/Colon
Secretion ~ None
Function ~ The large intestine is mainly involved with the absorption of water and electrolytes from the undigested substance, that is passed on to it from the small intestine. It also stores this undigested material till it is ready to be excreted from the body through the rectum and the anus.

The gallbladder, a tiny pear-shaped sac that is located under the liver, is also an important organ. It stores and concentrates the bile produced by the liver. Bile is essential for digestion of fats. But, surgical removal of gallbladder (in case of severe infection) does not affect the process of digestion. So, gallbladder is termed as a non-vital organ. Apart from the pancreatic juices, the pancreas also makes insulin, which directly enters the bloodstream. Insulin plays an important role in regulation of blood sugar level. The liver produces various chemicals that are required for proper functioning of the body. It plays an important role in detoxification of potentially harmful chemicals.
Digestive System Facts
Here are some facts about the digestive system:
• We produce almost one quart of saliva every day.
• Saliva is 98% water and only 2% enzymes.
• Length of the digestive tract is about 30 feet.
• Food stays in the stomach for almost 2 to 3 hours.
• The small intestine is almost 20 feet long.
• Food takes almost 4 hours to travel through the small intestine.
• The large intestine measures up to 5 feet in length.
• We excrete solid waste material through the anus, when the sphincter muscles lining it, relax.
• Liver and pancreas are not a part of the digestive tract but they help in digestion by secreting powerful enzymes.
So, you can see how the various digestive system organs work in coordination with each other to break down the food we eat into simpler forms. The system promotes absorption of the essential nutrients by the cells of our body. Proper functioning of the digestive system is very important for both our digestive health and our overall health.
After you have read the article, try to identify and mark the various organs in this ready-to-use human digestive system diagram - blank worksheet to label. All the best!
Model Of The Digestive System
Digestive System Diseases