What is the digestive system used for?

The organs afferent to the digestive tract allow the intake, processing and absorption of food and the elimination of residues .

Table of Contents

The mouth

It designates the opening of the digestive canal on the external environment and the cavity inside which the opening itself is included. It is supported by a skeletal arch divided into a maxillary (upper) and a mandibular (lower) portion , each of which has teeth . Anteriorly it is delimited by the lips ; posteriorly from the throat . In addition to representing the initial part of the digestive tract, the mouth also has respiratory and phonatory functions and is the seat assigned to the perception of taste .

The epiglottis

It is an elastic cartilage covered with a mucous membrane located at the root of the tongue . Its function is to prevent chewed food and saliva from going into the airways (or “crosswise”): it is for this reason that, during swallowing , it lowers on the opening of the larynx – to close it temporarily – preventing the access to the food bolus.

The pharynx

It is a canal that connects the throat with the esophagus . Musculo-mucous structure, it represents both the first part of the digestive tract – in fact it receives the food bolus from the mouth through swallowing – and a part of the upper airways: in fact the air coming from the nose , which from the pharynx enters the larynx. The alimentary and airways therefore flow into the pharynx; these then continue – separately – into the esophagus and larynx respectively.

The esophagus

It is the portion of the alimentary canal that reaches the stomach from the pharynx. Through this organ, of a muscle-mucous nature , the food bolus passes – that is, the food chewed by the teeth and partially digested by the enzymes of the saliva – coming from the mouth and directed to the stomach. The passage of the bolus is facilitated by the contraction of the muscular component that is present in the wall of the esophagus.

The stomach

It is the organ that is responsible for receiving food from the mouth , and therefore chewed and partially digested by the saliva enzymes, from which it arrives through the passage in the pharynx and esophagus. Here the food is scrambled and further digested through the action of gastric juices . Above, the stomach communicates with the esophagus by means of an anatomical region of conjunction known as the “cardias” , while below it opens into the small intestine by means of the pylorus, a muscular formation that regulates the access of the gastric contents to the intestine.

The liver

It is the most voluminous gland in the body . It is connected to the digestive system and performs various functions, not only useful for the digestion of food, but also for the defense of the organism and the elimination of toxic substances. From the digestion point of view, the liver facilitates the transformation of absorbed foods through the emulsion of fats, the synthesis of glucose, cholesterol and triglycerides , and also controls the metabolism of proteins. Vitamin B12 , glucose, iron and copper are also stored inside .

The pancreas

It is an elongated cone-shaped gland which is responsible for both endocrine secretion ( secretion process in which the secretion is directly introduced into the bloodstream) and exocrine secretion (secretion process in which the product is placed in a natural cavity of the organism or released outside). Positioned almost horizontally , it is located in the upper part of the abdomen, arranged transversely and behind the stomach , at the level of the first two lumbar vertebrae. It is the exocrine secretion of the pancreas that plays a determining role in the food digestion process: thethe end product of exocrine secretion is in fact pancreatic juice , or a liquid inside which there are several enzymes essential for digestion (lipase, amylase, etc.).

The small intestine

Also called “small intestine” , it represents the most developed portion (in length) of the intestine. About seven meters long , it is divided into three portions : duodenum, jejunum and ileum . It flows into the large intestine – or large intestine – via the ileocecal valve (or Bauhin valve) . The mucous membrane that lines its internal walls is covered by the so-called “intestinal villi” , responsible for the absorption of nutrients introduced through food, and circular folds (their presence is useful for expanding the surface, so that it performs its tasks better than completion of digestion and absorption of nutrients).

The large intestine

Also known as “large intestine” , it represents the final part of the intestine and, more generally, of the digestive system. It extends from the ileocecal valve (or Bauhin valve) to the anal orifice . Its function is to end the digestive process by absorbing, fermenting and evacuating the ingested foods. It is about 1.5 meters long overall.