63 Digestive System Facts That You Must Know About Your Body

The digestive tract is a series of connected organs leading from the mouth to anus through which food is taken in and digested into nutrients that can be absorbed into the body. 

The adult human digestive system consists of the G-tract. This comprises a mouth with teeth for mastication (chewing), an esophagus (or gullet), a stomach, small intestine, large intestine, rectum, and anus.

A healthy digestive process requires vital nutrients for a healthy immune system. Gut flora is the bacteria that help in the digestive process. Food particles are softened in the mouth with the help of saliva. 

Digestive disorders include abdominal pain or bloating, particularly after eating, heartburn, nausea or vomiting, diarrhea or constipation, blood in the stool, jaundice, and many others. A sedentary lifestyle and stress can interfere with proper digestion and reduce the ability to absorb nutrients from food. Symptoms differ based upon the ailment and the type of food you've consumed. Excessive intake of alcohol and caffeine drinks reduces the body's ability to digest properly. Smoking damages cells of the mucous membranes lining the GI tract and impairs the blood supply to that area, leading to slow healing. 

If you suffer from digestive problems, it is recommended you eat light food, so that food is easy to digest in the small intestine. 

Collagen also has several roles in the human body, which include helping maintain structure and strength in skin, tendons, ligaments, cartilage, bones, and teeth. But did you know that collagen plays a role in the digestive system, by helping to maintain healthy digestion through the effective movement of food through the intestines?

Have you found out some interesting facts about your digestive system? If you want to learn more, including the history, components, and clinical significance of the GI tract, then read on.

Components Of The Digestive System

The digestive system, otherwise known as the GI tract, is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The organs include the mouth, esophagus (gullet), stomach, small intestine, large intestine (or colon), rectum, and anus. 

The mouth is the first part of the digestive-system process, where the food goes after ingestion.

Saliva is produced by salivary glands, which soften food and contain the enzyme amylase, which catalyzes the breakdown of carbohydrates found in foods such as bread, starchy vegetables, and grains.

Saliva also helps clean teeth by washing away bacteria.

The esophagus is a muscular tube that transfers food and liquids from the mouth to the stomach through peristalsis.

The stomach receives food via esophageal muscle contractions and gastric juices produced by the cells of the stomach's mucous lining.

Hydrochloric acid (HCl) gives the stomach lumen (the cavity) its acidic pH (between 1 and 3).

Pepsinogen is an inactive precursor of the enzyme pepsin that is also produced by cells in the stomach lining.

Chief cells are found primarily in the upper portion of the stomach near the pyloric sphincter and produce several enzymes, including rennin, which breaks down proteins.

G cells in the stomach lining produce a substance called gastrin that stimulates parietal cells to secrete hydrochloric acid. 

The duodenum, jejunum, and ileum are the three sections of the small intestine.

The duodenum secretes digestive juices that contain enzymes, bicarbonate, and intrinsic factors necessary for the breakdown of proteins, fats, and carbohydrates, and the absorption of vitamin B12.

Bile produced by the liver helps the small intestine break down fats into smaller molecules called fatty acids.

Unlike saliva in the mouth, these enzymes start to work on fully chewed food.

All enzymes are proteins that speed up chemical reactions inside the body.

In the large intestine, indigestible food matter is broken down into water, mineral salts, and organic chemicals that can be absorbed into the bloodstream through membranes lining the colon wall.

The large intestine absorbs vitamin K and some B vitamins, but most of these vitamins are reabsorbed in the jejunum.

The large intestine absorbs around 0.79 gal (3L) of water a day, which turns solid waste matter semiliquid.

In summary, most digestion occurs in the small intestine and colon, with some absorption taking place there as well.

Fecal matter is passed from the last part of the large intestine before it reaches the rectum and anus.

The rectal recumbency stores feces during defecation (the elimination of solid waste matter from the body via the anus).

The circular muscle layer around the rectal opening relaxes, allowing feces to exit the body through the anus.

As gas builds up, pressure in the anal canal becomes greater than that in the rectum, so feces also exit via the anus.

The external and internal anal sphincters, as well as the puborectalis muscles, tighten and loosen during excretion, allowing waste products to pass from the human body.

The anus is a distal opening of the gastrointestinal tract that allows fecal waste to be excreted from the body. It is located between the buttocks, posterior to the perineum.

The human digestive system processes food to extract energy and building blocks for cell growth. All anabolic reactions in the body occur here.

Food is made up of mostly water (about 70% by weight) as well as lipids, proteins, polysaccharides, and various other substances.

A series of organs make up the digestive system, hollow organs joined in a long, twisting tube from the mouth to the anus.

Organs such as the stomach and intestines create muscle contractions that push food through the tube, while other organs such as the liver and pancreas add enzymes and fluids that help with digestion.

Blood Supply To The Digestive Tract

Blood gets to the digestive system through the celiac trunk (superior mesenteric artery) and is distributed through branches that form a web-like structure called the coeliac plexus. Read oil to find out more but the blood supply to the GI tract.

Blood enters both abdominal cavities via a variety of arteries, veins, and lymph vessels, including the superior pancreaticoduodenal, gastroduodenal, hepatic portal vein, a cystic branch of the hepatic artery, the middle colic artery, and the inferior pancreaticoduodenal.

Although the liver lacks nerve cells, a large part of your overall blood flow goes to the liver. It receives 0.26 gal (1L) of blood every minute via the superior mesenteric artery, which branches into two hepatic arteries.

Hepatic veins bring deoxygenated blood from the liver back to the heart after it processes toxins, chemicals, and byproducts of metabolism.

The portal vein carries venous blood-carrying digested nutrients from the intestine to the liver for processing before being distributed throughout the body through the superior mesenteric vein.

Blood circulation in the digestive tract of the human body is known to increase after half-an-hour of digestion and is known to last for fewer than two hours.

Clinical Significance Of The Digestive System

The digestive system is the part of the body where many diseases start, especially in industrialized societies. Read on to find out more.

There are several different kinds of digestive disorders, including infectious, genetic, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), metabolic, and nutritional disorders.

Several disorders involve the mouth, stomach, and intestines, such as malnutrition, GI bleeding, constipation, GERD (gastroesophageal reflux disease), Crohn's disease (inflammatory bowel disease), ulcers, and acid reflux.

Heartburn occurs when there is a regurgitation of acidic stomach contents up towards the esophagus, which causes inflammation and pain in the lower chest or upper abdomen.

The main cause of digestive system diseases is thought to be a combination of age-related changes in each part of the system as well as modern factors such as processed food diets and an increase in sedentary behavior.

Digestive disorder symptoms include cramping, abdominal pain, diarrhea, constipation, bloating, and more.

Most commonly, they result from a problem with how quickly or slowly food particles pass through the intestines.

Inadequate absorption from the intestine can also lead to malnutrition or dehydration due to poor nutrient intake.

Functional bowel disorders include functional dyspepsia or irritable bowel syndrome (IBS), often due to intestinal bacterial overgrowth.

Inflammatory bowel diseases (IBD) include Crohn's disease and ulcerative colitis. It can lead to severe diarrhea, weight loss, anemia, fatigue, abdominal pain, and other symptoms.

Ulcers are mucosal injuries caused by exposure of the epithelial lining to digestive acids or enzymes in the stomach, or bacterial problems.

Gastrointestinal stromal tumors (GISTs) are rare adult cancers that develop from cells called interstitial cells of Cajal, a special type of cell in the GI tract. These tumors can cause major problems with eating and digestion.

Other conditions that affect the heart and blood vessels can also cause problems with digestion, such as gastroparesis or diabetic autonomic neuropathy.

Additionally, cancer involving the pancreas and liver, particularly metastatic disease to the liver, can cause digestive problems.

The History Of The Digestive System

If you have enjoyed reading these digestive-system facts, read on to find out more about the history of medicine regarding the GI tract.

Islamic philosopher and physician Avicenna (980 A.D. to 1087 A.D.) contributed knowledge on a variety of topics, including medicine, and 40 of his medical texts survive. In his most famous, he discusses 'rising gas'. Avicenna believed that a malfunction of the digestive system led to excessive gas production in the stomach. For its cure, he suggested a combination of herbal medicines and lifestyle modifications.

In 1497, Venetian surgeon general Alessandro Benedetti regarded the stomach as a dirty organ separated from the diaphragm by a membrane.

It wasn't until the mid-17th century that the concept of the digestive system was generally accepted.

Polymath Leonardo da Vinci sketched organs of the digestive system during the 16th century Renaissance. He was convinced that the digestive system assisted with respiratory function.

Also during the Renaissance, physician Andreas Vesalius drew pictures of the inside of people's stomachs, and is said to be the founder of modern human anatomy.

In the mid-17th century, a doctor from Flanders, Belgium, named Jan Baptist van Helmont offered a description of digestion that was very similar to modern enzyme theory.

William Harvey, in 1653, described the intestines' length, supply of blood, and mesenteries.

Hydrochloric acid in gastric juices was first described by William Prout in 1823.

GI Tract FAQs

What are the three important functions of the digestive system?

The breakdown of food into constituent parts, such as proteins, fats, and carbohydrates, is possible with the help of the digestive system. It also acts as an important part of the immune system by manufacturing antibodies that fight infection and help other cells in the body destroy harmful substances. Lastly, it produces hormones that are used throughout the body to control blood-sugar levels, send messages between cells, and trigger reactions in cells. 

What is the function of the digestive system?

The function of the digestive system is to break down food into small components that can be absorbed through the wall of the digestive tract. Vital nutrients are absorbed from food, which is essential for a healthy body.

How does the digestive system work?

The digestive system works when the actions of muscles, hormones, and enzymes break down food into smaller components that can be absorbed by cells.

How many organs are in the digestive system?

The digestive system is made up of eight organs. 

What is the purpose of the digestive system?

The digestive system's function is to convert food into energy through smaller particles that can then be assimilated through the digestive tract's membranes. The products of digestion are then taken into the blood and lymph systems, where they are spread throughout the body.

What does the large intestine do in the digestive system?

The large intestine receives undigested food from the small intestine, water from the body, and bacteria that live in the large intestine help to digest food and extract remaining water from undigested material.

What does the liver do in the digestive system?

The liver produces bile, which is used in the process of food digestion. Bile helps the body digest fats from food.

What organs make up the digestive system?

The digestive system consists of the mouth, esophagus, gut, stomach, liver, gall bladder, pancreas, small intestine, and large intestine.