The digestive system, its function and parts

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Digestion is vitally important because the body requires nutrients from food to function properly and stay healthy

The digestive system chemically breaks down nutrients into very small parts so that the body can absorb them and use them to generate energy, as well as for cell growth and repair.

The mechanism that the digestive system employs to accomplish its functions is worthy of analysis. Studying how it works will increase our appreciation for this intricate and beneficial system.

What is the digestive system? Its parts

The digestive tract consists of the gastrointestinal tract, liver, pancreas and gallbladder. The gastrointestinal tract is made up of a series of hollow organs joined together in a long, twisted tube that runs from the mouth to the anus

The hollow organs that make up the gastrointestinal tract are the mouth, esophagus, stomach, small intestine, large intestine and anus. The liver, pancreas and gall bladder are the solid organs of the digestive tract.

The small intestine in turn consists of three parts. The first is the duodenum, the jejunum is in the middle and the ileum is at the end. It also includes the appendix, a small finger-shaped pouch attached to the cecum. The cecum, on the other hand, is the first part of the large intestine, the colon is next and the rectum is the final part of the large intestine.

How does the digestive system work?

The parts of the digestive system work together to help move food and fluids through the gastrointestinal tract and to chemically break down food

Digestion is a six-step process: ingestion, propulsion, mechanical breakdown, chemical digestion, absorption and elimination. In the first step, food is swallowed, chewed and swallowed. Subsequently, muscle contractions propel them through the digestive tract

Digestive fluids chemically break down food nutrients into molecules. After the food has been chemically broken down, the body can absorb and transport the nutrients to where they are needed, including carbohydrates, proteins, fats, minerals and vitamins. Finally, undigestible substances are eliminated as waste.

The body has an enteric nervous system, composed of nerves within the walls of the gastrointestinal tract. When food stretches the walls of the gastrointestinal tract, these nerves release many different substances that accelerate or delay the mobilization of food and the production of digestive juices

Intervention of the different organs in the digestive process

Food is transported through the gastrointestinal tract by a process called peristalsis. In this process, the organs of the digestive system intervene as follows:

  • Mouth. When swallowing, the tongue pushes the food down the throat. The epiglottis folds over the trachea to prevent the person from choking and food from passing into the esophagus.
  • Esophagus. The brain sends signals to the esophageal muscles and peristalsis begins. When food reaches the end of the esophagus, the lower esophageal sphincter relaxes and allows food to pass into the stomach
  • Stomach. Its muscles mix the food with digestive juices. It then empties its contents into the small intestine.
  • Pancreas. It produces a digestive juice that has enzymes that break down carbohydrates, fats, and proteins and delivers it to the small intestine.
  • Liver. Produces bile that digests fats and some vitamins, transports it to the gallbladder for storage or to the small intestine for use.
  • Gallbladder. Stores bile between meals. When a person eats, it sends bile into the small intestine.
  • Small intestine. Its muscles mix food with digestive juices from the pancreas, liver and intestine and push the mixture forward
  • Large intestine. Waste from the digestive process is transformed into feces by absorbing water and moves into the rectum, which pushes it out of the anus during defecation.

What happens to the digested food?

The small intestine absorbs most of the nutrients present in food and the circulatory system is responsible for passing them to other parts of the body for storage or later use

There are special cells whose purpose is to help the absorbed nutrients cross the intestinal lining into the bloodstream. In the blood, simple sugars, amino acids, glycerol and some vitamins and salts are transported to the liver

The liver stores, processes and distributes nutrients to the rest of the body when needed.

The lymphatic system, a network of organs, nodes, ducts and vessels that produce and transport lymph from the body’s tissues to the bloodstream, helps maintain fluid balance in the tissues and blood, providing nutrients, oxygen and hormones to the cells. It also fights infection and filters out foreign organisms and waste.

On the other hand, the body uses sugars, amino acids, fatty acids and glycerol to develop substances required for energy, cell growth and repair.

It is incredible to think that when we ingest food, we are contributing to all these bodily processes that are fundamental for life.

Tips to keep the digestive system healthy

It pays to take care of this important system. Some of the measures that can be taken are the following:

  • Consume fiber. The insoluble vegetable fiber retains water in the final portion of the large intestine, this makes the stool have a softer consistency, which facilitates defecation
  • Eat fruits and vegetables. These foods provide water, fiber and vitamins and minerals. The pectin in apples, the mucilage in figs and the starch in potatoes and rice protect the intestinal mucosa. In addition, fruits and vegetables are the major source of antioxidants.
  • Drink enough water. It is recommended to drink 1.5 to 2 liters of water a day, as it facilitates digestion and prevents constipation.
  • Moderate the intake of fatty foods. Fatty foods such as margarine, bacon, lard, fatty meats, sausages and cured cheeses, should be consumed in small quantities, to lighten digestion.
  • Exercise. Moderate exercise promotes intestinal motility.

The digestive system performs a multitude of functions aimed at making the best use of the nutrients in food. If we eat in a healthy and moderate way, we will be giving a caress to this very useful system.

German Fuertes Otero
German Fuertes Otero
CEO at M.D. from Stanford Medicine: Stanford, California, US, M.Sc. from University of Cambridge: Cambridge, Cambridgeshire, UK and University of Oxford: Oxford, Oxfordshire, UK. PhD at Harvard University Harvard Catalyst: Cambridge, MA, US.

Aunque pueda contener afirmaciones, datos o apuntes procedentes de instituciones o profesionales sanitarios y la información contenida en PharmaSalud esté redactada por profesionales en medicina, recomendamos al lector que cualquier duda relacionada con la salud sea consultada con un profesional del ámbito sanitario.

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