digestive system and its functions

digestive system

digestive system is a group of hollow organs that allow food to pass and digest from the mouth to the anus. 
It has a length of 9 meters. The components of the human digestive system include the mouth, pharynx, esophagus, stomach, small intestine and large intestine.
Also, teeth, salivary glands, tongue, liver, pancreas, and gallbladder vesicle are additional components of the digestive system.  
Each has a role in completing the digestive system function, which is called digestion, and it is the process by which food particles are broken down into small, easily absorbed ones.
The human digestive system is lined from the inside by a membrane known as the mucosa. 
It is found in the mouth, stomach and small intestine, and this membrane contains small glands , that secrete substances that aid in the digestive process.
Also, the cells of the mucous membrane of the small intestine contain several special systems. 
It works to ensure complete absorption of carbohydrates, proteins, fats, vitamins, water and salts.
The digestive system is the gateway for nutrients to enter the circulatory system (heart and blood vessels). 
Which delivers it to all parts of the body, and before this happens, large food particles must be broken down into , very small particles by the digestive system.

Digestive system components and functions

Every part of the human digestive system performs its function , and acts as a basic machine in this factory, that works with extreme efficiency and precision.
  • (salivary glands):
The salivary glands are one of the most important components of the digestive system. 
They are tissues located around or inside the oral cavity and work on producing saliva.  Which is transported through one or more glandular ducts that open into the oral cavity. 
There are three main salivary glands: the parotid gland, submandibular gland and sublingual gland.
Saliva is made up of a mixture of water, mucus, antibacterial substances and digestive enzymes such as amylase. 
Saliva breaks down the starch in our food, moisturizes the mouth and the rest of the digestive system, forms a bite of food, and cleans the mouth and teeth.
  • (the mouth):
 It is the entrance to the digestive system, and digestion usually begins. 
It has several functions in the digestive system, such as chewing food with the teeth, stirring and moisturizing it, forming a bite of food and pushing it with the tongue towards the throat.
  • (Pharynx):
 It connects the mouth and the nose with the throat and the esophagus. 
It is a molecule from both the digestive and respiratory systems, which passes the breathing air through the larynx.  And the food passes through it into the esophagus.
  • (esophagus):
 It is a muscular tube that extends from the lower end of the pharynx to the stomach.  it transfers the morsels of food through a series of repeated contractions in his wall. 
At its lower end there is a muscle sphincter , that prevents the return of food from the stomach towards it, with what is called regurgitation or gastroesophageal reflux.
  • (Stomach):
 The stomach is one of the most important parts of the digestive system.  It is a hollow organ that prepares a morsel of food for digestion. 
By secreting a group of digestive enzymes that break down food into easily absorbed elements. 
It is mainly responsible for digesting the proteins in meat by mixing it with the sour gastric juice. 
After the stomach is finished working, it pushes its content into the small intestine, where the digestion process continues.
  • (Small intestine):
The small intestine is about seven and a half meters long. 
It is a muscular tube that digests food and absorbs important nutrients.  Which is transported through the blood vessels to all cells of the body.
  •  (Large intestine):
 The large intestine, or colon, begins at the end of the small intestine.  At the point of their connection, the appendix is ​​placed.  The length of the large intestine is about one and a half meters. 
The remaining nutrients are absorbed by it and the fecal mass is formed from undigested food waste.  Then it has an essential role in making some B and K vitamins.
It usually takes 36 hours for food to cross the colon through contractile movements.  The large intestine ends with what is called the rectum.
  • (Rectal):
 It is the last part of the digestive tract that opens out of the body, into the anus.  It reaches a length of 20 cm and completes the absorption of water from the fecal mass. 
When the rectum is filled, the stool is preserved and the person feels the need to defecate.
The liver is one of the most important parts of the digestive system: 
The liver is located in the upper right of the abdominal cavity.  It has many important functions for the body.
but its primary function as a member of the digestive system , is to activate the nutrients absorbed within the intestine. 
It is a manufacturer of chemicals in the body , that convert the absorbed primary elements into a group of substances that the body needs in its various functions. 
Then it has an important function in fighting harmful toxins to the body, and absorbing and detoxing many medicinal substances.
  • (Gallbladder):
The gallbladder lies below the liver and connects to it with the bile duct.  It is a hollow sac that stores the bile secreted by the liver. 
When fatty substances enter the small intestine, the gallbladder wall contracts to secrete bile. which has an important role in the digestion of these substances.
  • (Pancreas):
The pancreas is known to regulate blood sugar levels by acting as a gland , that secretes the hormone insulin directly into the blood vessels. 
But the pancreas is an important component of the digestive system.  It works by secreting various digestive enzymes , through  its duct in the small intestine. 
These enzymes have an essential role in digesting protein, carbohydrates and fats.

The function of the digestive system

The function of the digestive system convert food and liquids to its basic elements. such as: fats, proteins, vitamins, and carbohydrates to be used.
as these elements cannot be absorbed from the digestive system through the blood , before they are converted from their large, complex forms into small and simple forms. after these elements are absorbed, it is useful.
It is used in the body to repair cells, grow, and produce energy.  
the digestion period is estimated between 2-5 hours, from entering food through the mouth to getting rid of it. through the anus in normal cases.
as the process of digesting food in the stomach and intestine needs a period ranging between 6-8 hours. 
While it takes about 36 hours for food to pass through the colon. it is worth noting that the duration of the digestive process varies between individuals, and between men and women.
One of the most important functions of the digestive system is movement. This function is responsible for the movement of food from the mouth to the anus , and takes place in four stages:
  • Ingestion:
simply entering food into the mouth.
  • Mastication:
It means breaking down large food particles into smaller ones that are easier to swallow. as well as mixing them with salivary secretions inside the mouth.
  • Deglutition:
It means the passage of food from the mouth to the stomach, through the pharynx and esophagus.
  • Peristalsis:
This is a group of continuous, rhythmic contractions that are responsible for the passage of food through the digestive system.


The stages of processing and digesting food in the human body

  • Eating:
It is the process of eating food.
  • Pushing:
it is the movement of food along the digestive system. The primary mode of propulsion is the peristaltic or vermicular movements of the muscles.
which are a series of alternating contractions and relaxations in the smooth muscles. that line the digestive system and that push food along it.
  • The secretion of digestive enzymes and other substances that liquefy food, adjust its pH, and chemically break it down.
  • Mechanical digestion 
it is the process of physical breakdown of food into smaller pieces.  This process starts from chewing food to milling that takes place in the stomach and small intestine.
  • Chemical digestion ;
it is the process of the chemical breakdown of food into simpler molecules.  This process is carried out by enzymes in the stomach and small intestine.
  • Absorption:
it is the process of transporting particles (by passive diffusion or active transport) , from the inside of the digestive pathway to the adjacent blood and lymph vessels.
  • Excretion ;
it is the process of removing undigested material from the anus.

What happens to digested food?

Most of the nutrients in food are absorbed by the small intestine. which pass through the blood circulation to other parts of the body for storage or use.
Specialized cells help nutrients absorbed from the cells lining the intestine , pass into the bloodstream. The blood carries simple sugars, amino acids, cholesterol, and some vitamins and minerals to the liver.
The liver stores nutrients, processes them, and delivers them to the rest of the body when they are needed.
The lymphatic system, which is a network of vessels that carry white blood cells and a fluid called lymph, through a fluid throughout the body. in order to fight infection, absorbs fatty acids and vitamins.
The body uses sugar, amino acids, fatty acids, and glycerol to create the substances they need for energy production, growth and cell repai.

How to maintain the health of the digestive system?

 The foods that a person consumes or the lifestyle followed may affect the health of the digestive system. 
it is worth noting that following some important steps to improve the health of digestion , will help increase the efficiency of the digestive system.
improve the general health of the person. the following is a list of some tips that are followed to maintain the health of the system digestive:
  • Eat a healthy diet rich in fiber, because fiber increases bowel movement, which reduces the risk of constipation.
  • Reducing high-fat foods, because fats reduce bowel movements, which increases the risk of constipation.
  • Drink water in ample quantities to improve the digestion of food.


  • Exercising regularly.

Continuous movement, regular physical activity and regular exercise are necessary to obtain proper digestion resulting from , improving bowel movement and speeding up the movement of food breakdown through the gastrointestinal tract, which avoids intestinal cramps and constipation.

  • Avoid bad habits such as: smoking, drinking alcohol, and excessive drinking of caffeine.
  • Control the level of stress in your daily life that negatively affects the health of the digestive system.