Digestive System of Human Body

The digestive system can be understood as the system of organs responsible for the below tasks:

  • Getting food into and out of the body
  • Breaking the food into nutrients to keep the body healthy

These two simple but complex processes require the help of multiple parts of the body. The human digestive system includes:

  1. Mouth
  2. Esophagus
  3. Stomach
  4. Small intestine
  5. Pancreas
  6. Liver
  7. Gallbladder
  8. Colon
  9. Rectum
  10. Anus

All these organs comprising of the digestive system are joined in a long, twisting tube from the mouth to the anus. There is a further intricate process consisting of ducts, mucosa and other systems like nerves and blood that have a potential role in ensuring the working of the digestive system.

In the present article, we will help you in understanding what digestion is and how each organ works within the system to manage our daily affairs.

Understanding Digestion First

Digestion can be in simple terms defined as the process of breaking down the food.

This process is an intricate and interesting one to know in-depth. So what happens after you place your food in your mouth? Between the production of energy and the formation of waste, there is a long procedure carried out within your body.

This process is carried out in the gastrointestinal tract which is a long, connected, tubular structure initiating with the mouth and ending with the anus. The food is pushed forward within the system, transformed by enzymes and hormones into usable particles and absorbed along the way. Further, the organs like the liver, gallbladder, and pancreas perform their role in the digestive system.

Let’s understand how each part of the digestive system plays its role.


The mouth is the starting point of the digestive tract. The minute you take the first bite of your meal, the process of digestion kick starts.

Often we hear about chewing properly. This is because chewing breaks the food into small pieces that are more easily digested.

At the same time of chewing saliva mixes with food to start the process of breaking it down into a form your body can absorb and use.


Also referred to as pharynx medically, the food from mouth reaches the throat from where it travels to the esophagus or the swallowing tube. Another passage linked to throat along with the esophagus is the windpipe which s connected to lungs and performs its set of functions.


The esophagus is a muscular tube extending from the pharynx to the stomach. Once the food enters the esophagus, it is moved down the esophagus and then into our stomach in a form of series of contractions called peristalsis.

There is an amazing system of contraction and relaxation of muscles behind and ahead of the food respectively. This mechanism is the main contributor to moving the food forward to the stomach. GH our digestive system.

Just before linking to the stomach there is a zone of high pressure known as the lower esophageal sphincter. It is a “valve” meant to keep food from passing back into the esophagus which prevents heartburn or regurgitation.


The stomach serves multiple purposes. Apart from holding the food, it also acts as a mixer and grinder. The stomach secretes acid and powerful enzymes that continue the process of breaking down the food and transform the food in a form of paste or liquid form when leaving the stomach. Now the food moves to the small intestine.

Small Intestine

The small intestine is like a long tube coiled in the abdomen loosely. It is made up of three segments, the duodenum, jejunum, and ileum.

The small intestine continues the process of breaking down food by using enzymes released by the pancreas and bile from the liver. Bile is a substance that aids in the digestion of fat and eliminates waste products from the blood.

Peristalses (contractions) play a role here as well. These enable moving food through and mixing it up with digestive secretions.

The duodenum is mainly responsible for continuing the process of breaking down food, with the jejunum and ileum being responsible for the absorption of nutrients into the bloodstream.


The pancreas secretes enzymes into the small intestine. These enzymes break down protein, fat, and carbohydrates from the food we eat.


The liver has multiple functions, but the two major functions for the digestive system are

  • To make and secrete bile which is stored in the gall bladder
  • To cleanse the blood coming from the small intestine containing the nutrients absorbed just


The position of the gallbladder is just under the liver where it stores bile made and traveled from the liver through a passage called the cystic duct.

Throughout the meal, the gallbladder shrinks and sends the bile to the small intestine. By now the nutrients are absorbed and the leftover liquid is passed through the small intestine. The left of the food is handed over to the colon or large intestine.

Colon (Large Intestine)

The colon is along the muscular tube that connects the cecum (the first part of the large intestine to the rectum (the last part of the large intestine).

The contractions (peristalsis) play a role here by passing over the waste left over from the digestive process through the colon. This is first in a liquid state and then in solid form as the water is removed from the stool.


The rectum is an 8-inch chamber that connects the colon to the anus. Rectum receives the stool from the colon and transfers it further to anus. Sending the sensory message to the brain, the brain decides if the rectal contents have to be released or not. Accordingly the rectum contracts or expands.


The anus is the last part of the digestive tract. It comprises of the pelvic floor muscles and the two anal sphincters (internal and external muscles). The internal sphincter controls us from going to the washroom when we are asleep and the role of the external sphincter can be understood when we feel the urge to go to the washroom but need to hold it till we get in.

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