The digestive system consists of the Alimentary Canal and various other organs whose primary function is to support the digestive system.

The Alimentary Canal is a long tube about 10 meters long, which begins at the mouth and ends at the anus. This tube consists of multiple sections which each have their own specific functions to perform in the process of digestion.

The sections of the Alimentary Canal in the order in which they process food are as follows:

Mouth
The teeth in the mouth help to physically crush and break up the food into smaller pieces to increase their surface area so that it can be processed in later stages of digestion. Also, saliva helps to soften food to make it easier to process, and also begins chemically breaking down the food so that it can be processed in later stages of digestion. The tongue helps to mix the crushed food with saliva.

Throat
The act of swallowing pushes the food from the mouth to the esophagus.

Esophagus (also called Oesophagus)
The Esophagus is a 10-inch long tube that connects the throat and stomach. Muscles in the wall of the esophagus contract in synchronized waves, called peristalsis, where the muscles behind the food contract, squeezing it forward, while muscles ahead of it relax, forcing it to advance towards the stomach.

Stomach
Powerful stomach muscles churn and mix the food, while glands in the walls of the stomach secrete acids and enzymes which chemically break down the food into very small particles and molecules, so that these can be processed in later stages of digestion.

Small Intestine
In the upper section of the small intestine, which is called the Duodenum, bile and pancreatic digestive juices mix with other juices secreted by the wall of the small intestine to continue the break down of food.

The food then enters the Ileum, the longest section of the small intestine, where nutrients are absorbed through the wall of the small intestine and transferred around the body via the blood stream (Circulatory System), to nourish and provide energy to all of the cells and organs of the body. This allows them to grow, repair, and perform the functions necessary to maintain life and fight disease, as well as allowing us to be able to move, think, breath, see, hear, and so on.

Large Intestine (also called the Colon and Bowel)
In the large intestine, nearly all of the water is absorbed, leaving a usually soft but formed substance called stool. Muscles in the wall of your colon separate the waste into small segments that are pushed into your lower colon and rectum.

Rectum
The Rectum provides a temporary storage place for the waste products of digestion. When the rectal walls are stretched, they signal the need for a bowel movement.

Anus
The powerful sphincter muscles in the Anus prevent the release of waste products from the Rectum until the person is ready to expel them from the body.

Various other organs in the body perform functions that are important to digestion or support digestion, and these organs include:

Gallbladder
The Gallbladder stores and concentrates bile, and then adds it to food as it enters the Duodenum, the upper portion of the small intestine.

Liver
The liver performs hundreds of useful functions, including nutrient storage, filtering and processing of chemicals contained in food, detoxifying harmful substances, purifying your blood, manufacturing vital nutrients, and producing bile, a solution that helps digest fats and eliminate waste products from the body.

Bile, a fluid secreted by the liver, is essential for the proper digestion of fats and for helping the body to rid itself of worn out red blood cells, cholesterol, and potentially toxic chemicals and metals. The liver is responsible for detoxifying harmful substances that a person may eat, drink, inhale, rub on their skin, or which enter the body in some other way.

Pancreas
The pancreas plays important roles in both digestion and metabolism, and is a large, long, flat gland which is located behind the lower part of the stomach and inbetween the duodenum (the upper part of the small intestine) and the spleen. Amongst other functions, the Pancreas produces digestive enzymes that help break down proteins, carbohydrates, and fats.

As a result of the digestive system, the body is able to extract nutrients from food and drink, and use these for growth, repair, and the maintenance of life; and process and discard waste products from the body as faeces (also called stools).

Each organ of the Digestive System and each section of the Alimentary Canal has specific and important roles to play in the digestion of the material we ingest.

The healthy transit time of food through a healthy human adult body (from mouth to anus) is less than 24 hours. However, recent research has shown that this time has been greatly extended beyond what is considered safe or healthy, particularly in the Western world, where the average is approximately 60 hours for men, and 70 hours for women. The reason for this is because of diet and lifestyle factors.

As a result, food is remaining in the body longer (almost 3 times as long as it should be), and taking longer to process, and this can elevate the risk of a range of health complications, such as constipation, digestive problems, bowel problems, and even bowel cancer.

Related posts:

1. How The Digestive System Works
2. Digestive System Facts

The organs and other body parts that constitute the digestive system have the common goal of turning what we eat and drink into nutrients that the body can use in one of two ways – either to grow cells that are needed for the purpose of bodily functions, or alternatively to use as energy to fuel those bodily functions. When functioning properly, the digestive system either breaks down the molecules of food and drink into smaller molecules, or it carries it to another part of the digestive system. Once the molecules are small enough for the body to be used to build cells or fuel the body, the digestive system (and the parts that aid the digestive system) then carry it to the cells of the body that use what the digestive system has been digesting.

There are six steps involved in accomplishing the task that the digestive system does. All of these six steps require movement through the system and a wave-like movement called peristalsis accomplishes the movement. Muscles that propel the food and liquid along the digestive tract accomplish peristalsis. Here are the six steps that are taken during the whole process of digesting what we eat and drink:

Step 1

The process begins when the body smells or tastes food and drink and salivates because of hunger or thirst as part of getting ready to eat or drink. We put the food and drink into our mouth and the first movement (swallowing) occurs. This first movement is a voluntary movement. It is voluntary because we decide to swallow, it is a conscious act on our part to do the swallowing. Once this first act of movement (swallowing) is accomplished all the other movements along the digestive tract are not involuntary. Involuntary means that the body automatically does it without our having to make the decision for the movement to happen. Our nerves control this involuntary movement action.

Step 2

The second step happens in the esophagus, which is what connects the throat and the stomach. The stomach is the first organ in the involuntary process that is under the control of our nerves. The esophagus moves what we eat and drink from the back of our throat to the entrance of our stomach.

Step 3

The third step involves the ring like valve that closes the passage between the two organs (esophagus and stomach). When the food gets near to the ring, the muscles around the ring relax and allow food to pass from the esophagus into the stomach.

Step 4
This is when the food enters the stomach, and completes the three tasks of the stomach. The three tasks that the stomach has to do with the food are to store it, mix it, and then empty it.

At the top of the stomach is the large muscle that relaxes in order to accept the large volumes of food and liquid that we take in each day. This is also where the stomach stores the food and liquid right after it accepts the material.

At this point the lower part of the stomach gets into the action, by mixing the food, liquid, and digestive juices that are produced by the stomach. This mixing action is accomplished by muscle action.

The last task of the stomach is to empty the contents of the stomach into the small intestine.

Step 5

This stage is where the food is digested into smaller molecules while it is in the small intestine . It dissolves the molecules of food by the juices of the pancreas, liver, and intestine, and then mixes the contents of the intestine and pushes them forward to allow for further digestion.

Step 6

The final step in the digestion process is where the nutrients from all of the digested material need to be absorbed by the walls of the intestine. The parts of the material that are not to be used as nutrients for the growth of cells or energy for the body are called “wastes”. The waste products are made up of not only the unused parts of what has been digested, but also of food parts that are known as “fiber”, older cells that have been shed by the mucosa. All of these waste products are now moved into the colon. Once in the colon the waste products remain for approximately one to two days until muscles move them along to be expelled as a bowel movement out your anus.

The end result of any of the tasks of the digestive system not functioning properly is a digestive system disorder. This could either be because of a congenital issue or because of some kind of illness that has affected the digestive process.

Related posts:

1. Digestive System Facts
2. What Is The Digestive System
3. What Are Digestive System Disorders?