What Is the Digestive System;How Does Digestion Work?

The digestive system  is the system consisting of the  organs  and  structures  that deal with the intake, processing and absorption of food , as well as the elimination of residues , that is, the parts of food that have not been digested.

The  organs  that make up the digestive system  are:

  • the  mouth
  • the epiglottis
  • the pharynx
  • the esophagus
  • the stomach
  • the liver
  • the pancreas
  • the small intestine
  • the large intestine .

The mouth

The  mouth  represents the connection with the outside of  the digestive canal . It also performs  respiratory and phonatory functions  and is the structure in which you have the  perception of taste .

Composed of two skeletal arches with  teeth  that take the name of  the  upper jaw and   lower jaw , it is delimited anteriorly by the  tongue  and posteriorly by the  throat .

The epiglottis

Located at the root of the  tongue , the epiglottis  is an elastic and rediscovered cartilage of mucous membrane which has the function, by closing during  swallowing , to prevent saliva and chewed food (food bolus) from ending up in  the airways .

The pharynx

The  pharynx  is the canal of  muscle-mucous structure  that puts the throat in contact   with the esophagus . The pharynx has a double function: it is the first part of  the digestive tract  but it is also a structure of  the upper airways .

Once passed by the pharynx, the  food bolus  will be introduced to the esophagus , while the air , coming from the nose, will be directed into the  larynx .

The esophagus

The esophagus  is the organ of muscle-mucous structure that is placed between the larynx and the stomach. The food bolus is introduced into the stomach  , i.e. the food chewed and already partially digested by the  enzymes of the saliva , whose passage to the next organ of the alimentary canal, the  stomach , is allowed by the contraction of the muscles present in its walls.

The stomach

The  stomach  is the organ of the digestive system where food is further  digested  through the action of  gastric juices .The stomach communicates in the upper part with the esophagus  through a valve that takes the name of  “cardias”  and in the lower part with the small intestine  through the  pylorus , valve that has the function of regulating the access of the  gastric content to the intestine. .

The liver

The  liver  is a  gland , the largest of the entire human body, which in addition to various other functions – to defend the body and eliminate toxic substances – also intervenes in the digestive process by promoting the  transformation of the foods  absorbed through the emulsion of fats and the synthesis of cholesterol, glucose and triglycerides. The liver also controls  protein metabolism  and stores it iron ,  copper , vitamin B12  e glucose .

The pancreas

The  pancreas  is a gland located in the upper part of the abdomen that produces  pancreatic juice , a liquid that contains many  enzymes  (lipase, amylase, etc.) essential for carrying out the  digestive process .

The small intestine

The small intestine  is also called the  small intestine . In truth it is the longest part of the intestine of the human body, almost seven meters. Made up of three parts – the  duodenum , the  jejunum  and the ileum  – it is connected to the large intestine through the  ileocecal valve .

The small intestine has the internal mucosa covered by the so-called  intestinal villi , structures that  absorb the nutrients  introduced with food, and by the  circular folds  which have the function of enlarging the intestinal surface so that the  digestive and absorption functions  of the nutrients are carried out in the best way.

The large intestine

The large intestine , also called the  large intestine , is the organ about 1.5 meters long which constitutes the final part of the digestive system, connected in its terminal part to the anal orifice .In this last portion of the intestine the digestive process is completed through the absorption ,  fermentation  and evacuation of the ingested foods .

What is the function of the digestive system

The digestive system  has the function of  taking ,  processing  and  absorbing food as  well as  evacuating the residues of foods  that have not been digested.

Which organs are part of the digestive system?

The digestive system can be imagined as a large tube through which food passes, which is broken down into simpler nutrients so as to facilitate their absorption.

The digestion is not a simple process confined to a single organ, each organ but carries out special functions:

  • Mouth: to all intents and purposes it starts the digestive tract. The digestion of food begins in the mouth, thanks to the combined action of the teeth that chop the food and the saliva that mixes everything to form a single body. Saliva contains digestive enzymes that initiate carbohydrate digestion. The saliva also lubricates the oral cavity facilitating the descent of the bolus into the esophagus.
  • Pharynx: short stretch of the digestive canal that connects the mouth to the exogafo.
  • Esophagus: is a tubular organ that extends from the pharynx to the stomach. The muscular component present in its wall gives rise to a series of contractions which are called peristalsis. Thanks to the peristaltic movements, the bolus can run in the direction of the stomach.
  • Stomach: it is a sacciform organ that receives food from the esophagus. The gastric mucosa produces the so-called gastric juices and digestive enzymes which continue the digestion of food. Food takes on the consistency of a mush and passes into the small intestine.
  • Small intestine: it is made up of three portions which are the duodenum , the jejunum and the ileum. At the duodenum level, the digestive phase of food continues, while fasting and ileum are mainly responsible for the absorption of nutrients to be introduced into the bloodstream. The duodenum in fact receives the enzymes produced by the pancreas and the bile produced by the liver . The liver and pancreas are two glands attached to the digestive system and participate in the digestive processes with their secretions.
  • Large intestine: water is absorbed in the latter part of the digestive tract. In addition, the intestinal flora is located at the level of the large intestine, consisting of several bacteria that perform a protective function against the organism. At the level of the large intestine, stools form, which are expelled from the body through the anus.

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