The digestive system is responsible for one of the most important functions of a living organism, i.e. nutrition. Here, food is taken, nutrients are absorbed, processed, and unnecessary residues are excreted. The human digestive system is an extremely complex, complicated and at the same time fascinating mechanism. Check how the digestive system is built and what is happening in each of its sections.

The human digestive systemis a group of organs that interact with each other, which is designed to provide the body with the ingredients needed to build and renew tissues, as well as water and energy substances necessary for the maintenance of all life processes.

The vast majority of nutrients (carbohydrates, fats, proteins), in order to be assimilated, must be digested beforehand, which consists in breaking down macromolecular organic chemical compounds into their simple building components. And that's what happens in the digestive system.

The digestive system consists of the digestive tract, about 8 meters long, and accessory glands. Its walls are usually made of three layers: on the inside - the mucosa covered with epithelium, inside - the muscular membrane that allows peristalsis, that is, the movement of food, and on the outside - protecting the serous membrane, the peritoneum, made of connective tissue.

  • oral cavity
  • throat
  • esophagus
  • stomach
  • small intestine
  • large intestine
  • anus

Digestive glands:

  • salivary glands
  • liver
  • pancreas

Oral cavity - structure, role, diseases

It all starts here. The oral cavity is bounded by the lips at the front, the palate at the top, the tongue at the bottom, and it connects to the throat at the back. There are teeth in the mouth that are used to grind and crush food. This mechanical treatment and mixing with saliva are the basic functions of the oral cavity.

The tongue is made of striated muscles. It serves not only to form bites of food and move them down the throat, but it is also an organ of the sense of taste.

The tongue is covered with a mucosa with taste buds and taste buds on them.

In the past, it was believed that individual flavorsthey are felt in well-defined parts of the tongue. However, this theory turned out to be incorrect, because in fact, each of the individual flavors can be perceived in any part of the taste organ.

Oral diseases:

  • periodontitis
  • gingivitis
  • tooth decay
  • thrush (thrush, oral candidiasis)
  • aptosis
  • herpes
  • erosions
  • lichen
  • benign tumors
  • tongue cancer

Esophagus - structure, role, diseases

The throat is the common section of the digestive and respiratory tract. It is an extension of the mouth and nasal cavity and continues into the esophagus and larynx.

The throat is made of striated muscles covered on the outside with connective tissue and on the inside with a mucosa. One of the laryngeal cartilages, the epiglottis, must function properly to prevent food from getting "out of place".

It closes when swallowing, and then the food slowly passes into the esophagus. But if, for example, we laugh while eating, it may happen that a little food gets into the respiratory tract, which gives the effect of choking.

Through the throat, a portion of food enters the esophagus, which is a kind of muscular-membranous tube, about 25-30 cm long. It starts at the 6th cervical and ends at the 10th-11th. thoracic vertebra.

The esophagus has no digestive function, it only transports food to the stomach with the help of perist altic movements.

Diseases of the esophagus:

  • reflux
  • esophageal tumors
  • dysphagia
  • esophageal diverticula
  • esophageal varices
  • achalazja
  • Mallory-Weiss syndrome
  • Barrett's esophagus

Stomach - structure, role, diseases

It is a kind of stretchy bag used to collect, process and sterilize food. It is lined with a mucosa with numerous glands that secrete gastric juice.

Gastric juice is a fluid containing hydrochloric acid, water, digestive enzymes, mucus and mineral s alts. The walls of the stomach are made of smooth muscles which, by contracting and relaxing, cause the food to move around and mix it with gastric juice.

This turns the food into mush. After 3-4 hours in the stomach, it moves to the intestine.

Stomach diseases:

  • stomach ulcer
  • Helicobacter Pylori
  • gastritis
  • dyspepsia
  • bezoary
  • Ménétrier's disease
  • acute hemorrhagic gastropathy(erosive)
  • acidity
  • stomach cancer

Small intestine - structure, role, diseases

It is the longest part of the digestive tract, 4-5 meters, 3-5 cm in diameter. This is where the digestion of food takes place and finally the absorption of nutrients into the blood and lymph. The small intestine is divided into three sections, these are:

  • duodenum- the first part of the small intestine, just behind the stomach. The tubes leading to the pancreas and liver go into the duodenum; It is them that the pancreatic juice from the pancreas and bile from the liver flows into the duodenum, thanks to which the food is broken down.
  • jejunum- further stage of digestion
  • ileum- the final stage of digestion and absorption. The intestine ends with an ileocecal valve.

The surface of the intestinal mucosa is covered with the so-called intestinal villi. These are the protrusions of the mucosa with capillaries and lymphatic vessels.

Thanks to them, the absorption area of ​​the intestine is increased. Not only that - there are also microvilli on the villi, thanks to which the surface of absorption increases even more.Diseases of the small intestine:

  • celiakia
  • cancer of the small intestine
  • irritable bowel syndrome (a disease of both the small and large intestine)
  • Crohn's disease (whole digestive system)
  • Whipple's disease
  • duodenal ulcer
  • parasitic diseases

Large intestine - structure, role, diseases

In this part of the digestive system, undigested food remains are formed into feces, but water, vitamin and amino acids are also reabsorbed. In addition, microorganisms multiply in the large intestine, which produce, among others, vitamin B12 and K. Jelito thick is divided into:

  • Cecum, Cecum- here gets the contents of the small intestine
  • colon
  • rectumending with anus

Colon diseases:

  • ulcerative colitis
  • acute appendicitis
  • anal abscess
  • hemorrhoids
  • anal fissure
  • fecal incontinence
  • microscopic colitis
  • colonic diverticula
  • colorectal cancer
  • constipation
  • infectionClostridium difficile

Salivary glands - structure, role, diseases

These are paired glands with orifices in the mouth. They produce saliva, or water secretion (water is 99% of its composition), which mixes with the food and helps in the initialdigestion.

Contains the enzyme salivary amylase (ptialin), which starts the breakdown of carbohydrates. In addition, thanks to saliva, food is easier to swallow, and it is also worth adding that the saliva has bactericidal properties.

There are: parotid, submandibular and sublingual glands.

Diseases of the salivary glands:

  • swollen salivary glands
  • inflammation of the salivary glands - mumps
  • bacterial salivary gland inflammation
  • Sjögren's syndrome (dryness syndrome or Mikulicz-Radecki's disease)
  • multiforme adenoma
  • salivary gland cancer

Liver - structure, role, diseases

It is the largest gland in the human body - it weighs about 1.5 kg - and is dark red in color, which means that it is very vascularized. It is located in the right part of the hypochondrium and consists of four lobes.

In the structure of the liver, there is a diverticulum of the hepatic duct, called the gallbladder, in which the bile produced by the liver is collected. Liver functions:

  • secretion of bile (bile is made up of bile s alts, cholesterol and bilirubin), which is essential in the digestion of fats
  • removing nutrients from the blood and thus helping to maintain systemic homeostasis
  • conversion of excess glucose into glycogen and its storage
  • conversion of excess amino acids into fatty acids and urea
  • gathering iron and some vitamins
  • neutralizing alcohol, stimulants and various pharmacological agents

Liver diseases:

  • Hepatitis A, B or C
  • cirrhosis of the liver
  • alcoholic liver disease
  • drug-induced liver damage
  • acute liver failure
  • autoimmune hepatitis
  • primary biliary cirrhosis
  • Wilson's disease
  • hemochromatosis
  • liver cancer
  • fatty liver
  • Buddha-Chiari syndrome (hepatic vein thrombosis)

Pancreas - structure, role, diseases

It is located behind the stomach, in the midline of the body and slightly to the left of the spine, in a loop formed by the duodenum. It weighs 60-125 g and is 20 cm long.

It consists of bubbles between which there are so-called Langerhans' islands, cells that secrete into the blood hormones related to carbohydrate metabolism.

The most important functions of the pancreas are the production of pancreatic juice containing enzymes that digest proteins (trypsin, chymotrypsin and erepsin) and collagen (elastase), and break down nucleic acids, and the production of hormones:insulin and glucagon that regulate carbohydrate metabolism in the body.

Pancreatic diseases

  • acute pancreatitis and chronic pancreatitis
  • insulinoma
  • pancreatic cancer

Category:

Gastrology