How food passes through the digestive organs. The process of digestion in the human body. Basic information about the mucous membrane

Diagram of the digestive system:

1. Oral cavity 3. Pharynx 4. Tongue 6. Salivary glands 7. Sublingual gland 8. Submandibular gland 9. Parotid gland 10. Epiglottis 11. Esophagus 12. Liver 13. Gallbladder 14. Common bile duct 15. Stomach 16. Pancreas 17. Pancreatic duct 19.Duodenum 21. Ileum(small intestine) 22. Appendix 23. Colon 24. Transverse colon 25. Ascending colon 26. Cecum 27. Descending colon 29. Rectum 30. Anal hole

Functions of the digestive system

· Motor-mechanical (grinding, moving, excreting food)

· Secretory (production of enzymes, digestive juices, saliva and bile)

· Absorption (absorption of proteins, fats, carbohydrates, vitamins, minerals and water)

· Excretory (removal of undigested food residues, excess of certain ions, heavy metal salts)

The human digestive system consists of the gastrointestinal tract and auxiliary organs (salivary glands, liver, pancreas, gall bladder, etc.).

There are three sections of the digestive system:

The anterior section includes the organs of the oral cavity, pharynx and esophagus. Here, mainly mechanical processing of food is carried out.

The middle section consists of the stomach, small and large intestines, liver and pancreas; in this section, mainly the chemical processing of food, the absorption of the products of its breakdown and the formation of feces are carried out.

The posterior section is represented by the caudal part of the rectum and ensures the removal of feces from the body.

Gastrointestinal tract

On average, the length of the digestive canal of an adult is 9-10 meters; It contains the following departments:

Oral cavity- a bodily opening in animals and humans through which food is taken and breathing occurs. The oral cavity contains the teeth and tongue. Externally, the mouth can have a different shape. In humans, it is framed by the lips. In the oral cavity, mechanical grinding and processing of food by enzymes of the salivary glands occurs.

Pharynx- part of the digestive tube and respiratory tract, which is the connecting link between the nasal cavity and mouth, on the one hand, and the esophagus and larynx, on the other. It is a funnel-shaped canal 11-12 cm long, with its wide end facing upward and flattened in the anteroposterior direction. The respiratory and digestive tracts cross at the pharynx.

Esophagus- part of the digestive tract. It is a hollow muscular tube flattened in the anteroposterior direction, through which food from the pharynx enters the stomach. The motor function of the esophagus ensures the rapid movement of a swallowed bolus of food into the stomach without stirring or pushing. The esophagus of an adult is 25-30 cm long. The functions of the esophagus are coordinated by voluntary and involuntary mechanisms.

Stomach- a hollow muscular organ located in the left hypochondrium and epigastrium. The stomach is a reservoir for ingested food and also carries out the chemical digestion of this food. The volume of an empty stomach is about 500 ml. After eating, it usually stretches to one liter, but can increase to four. In addition, it secretes biologically active substances and performs the function of absorption.

Small intestine- a section of the human digestive tract located between the stomach and large intestine. The digestion process mainly occurs in the small intestine: enzymes are produced in the small intestine, which, together with enzymes produced by the pancreas and gall bladder, help break down food into individual components. The small intestine is the longest section of the digestive tract; its mesenteric section occupies almost the entire lower floor of the abdominal cavity and partly the pelvic cavity. The diameter of the small intestine is uneven: in its proximal section it is 4-6 cm, in the distal section it is 2.5-3 cm.

Colon- the lower, final part of the digestive tract, namely the lower part of the intestine, in which water is mainly absorbed and formed feces are formed from food gruel (chyme). The large intestine is located in the abdominal cavity and in the pelvic cavity, its length ranges from 1.5 to 2 m. The inside of the large intestine is lined with a mucous membrane, which facilitates the passage of feces and protects the intestinal walls from the harmful effects of digestive enzymes and mechanical damage. The muscles of the colon work independently of the will of the person.

The role of accessory organs in food digestion

Digestion of food occurs under the influence of a number of substances -enzymes contained in the juice of several large glands secreted into the digestive canal. Ducts open into the oral cavitysalivary glands, allocated by them saliva moistens the oral cavity and food, promotes its mixing and the formation of a food bolus. Also, with the participation of salivary enzymes amylase and maltase, digestion begins in the oral cavitycarbohydrates . In the small intestine, namely in duodenum, secrete juice pancreas and a green-yellow, bitter-tasting secret liver- bile. Pancreatic juice contains bicarbonates and a number of enzymes, for example, trypsin, chymotrypsin, lipase , pancreatic amylase and nucleases . Bile, before entering the intestines, accumulates in gallbladder . Bile enzymes separate fats into small droplets, which speeds up their breakdown by lipase.

Salivary glands (lat. gladulae salivales) - glands in the oral cavity that secrete saliva. There are:

· Minor salivary glands (alveolar-tubular, mucoprotein, merocrine). The minor salivary glands are located deep in the oral mucosa or in its submucosa and are classified according to their location (labial, buccal, molar, lingual and palatine) or by the nature of the secretion (serous, mucous and mixed). The sizes of small glands are varied, their diameter ranges from 1 to 5 mm. The most numerous of the minor salivary glands are the labial and palatine glands.

· Major salivary glands (3 pairs): parotid, submandibular, sublingual.

Liver(lat. hepar, Greek jecor) is a vital unpaired internal organ located in the abdominal cavity under the right dome of the diaphragm (in most cases) and performs many different physiological functions. Liver cells form the so-called hepatic beams, which receive blood supply from two systems: the arterial vein (like all organs and systems of the body) and the portal vein (through which blood flows from the stomach, intestines and large digestive glands, bringing the necessary raw materials for the liver) . Blood from the hepatic beams flows into the inferior vena cava system. The bile ducts begin there, draining bile from the hepatic beams into the gallbladder and duodenum. Bile, together with pancreatic enzymes, is involved in digestion.

Human pancreas (lat. pancreas) - organ of the digestive system; a large gland with external and internal secretion functions. The exocrine function of the organ is realized by the secretion of pancreatic juice, which contains digestive enzymes for digesting fats, proteins and carbohydrates - mainly trypsin and chymotrypsin, pancreatic lipase and amylase. The main pancreatic secretion of duct cells also contains bicarbonate anions, which are involved in the neutralization of acidic gastric chyme. Pancreatic secretions accumulate in the interlobular ducts, which merge with the main excretory duct, which opens into the duodenum. The islet apparatus of the pancreas is an endocrine organ, producing the hormones insulin and glucagon, which are involved in the regulation of carbohydrate metabolism, as well as somatostatin, which inhibits the secretion of many glands, pancreatic polypeptide, which suppresses the secretion of the pancreas and stimulates the secretion of gastric juice and ghrelin, known as the “hunger hormone.” "(stimulates appetite).

Gallbladder is a bag-shaped reservoir for bile produced in the liver; it has an elongated shape with one wide end and the other narrow, and the width of the bubble gradually decreases from the bottom to the neck. The length of the gallbladder ranges from 8 to 14 cm, width - from 3 to 5 cm, its capacity reaches 40-70 cm³. It has a dark green color and a relatively thin wall. In humans, it is located in the right longitudinal groove, on the lower surface of the liver. The cystic bile duct at the porta hepatis connects to the hepatic duct. Through the fusion of these two ducts, the common bile duct is formed, which then unites with the main pancreatic duct and, through the sphincter of Oddi, opens into the duodenum at the papilla of Vater.

Nutrition is a complex process, as a result of which substances necessary for the body are supplied, digested and absorbed. Over the past ten years, a special science devoted to nutrition—nutritiology—has been actively developing. In this article we will look at the process of digestion in the human body, how long it lasts and how to manage without a gallbladder.

The structure of the digestive system

It is represented by a set of organs that ensure the absorption of nutrients by the body, which are a source of energy for it, necessary for cell renewal and growth.

The digestive system consists of: the mouth, pharynx, small intestine, colon and rectum.

Digestion in the human oral cavity

The process of digestion in the mouth involves grinding food. In this process, energetic processing of food with saliva occurs, interaction between microorganisms and enzymes. After treatment with saliva, some of the substances dissolve and their taste appears. The physiological process of digestion in the oral cavity involves the breakdown of starch into sugars by the amylase enzyme contained in saliva.

Let's follow the action of amylase using an example: while chewing bread for a minute, you can feel a sweet taste. The breakdown of proteins and fats does not occur in the mouth. On average, the digestion process in the human body takes approximately 15-20 seconds.

Digestive department - stomach

The stomach is the widest part of the digestive tract, has the ability to expand in size, and can accommodate huge amounts of food. As a result of the rhythmic contraction of the muscles of its walls, the process of digestion in the human body begins with thorough mixing of food with gastric juice, which has an acidic environment.

Once a lump of food enters the stomach, it remains there for 3-5 hours, during which time it is subjected to mechanical and chemical treatment. Digestion in the stomach begins with exposure of food to gastric juice and the hydrochloric acid that is present in it, as well as pepsin.

As a result of digestion in the human stomach, proteins are digested with the help of enzymes into low molecular weight peptides and amino acids. The digestion of carbohydrates, which begins in the mouth, stops in the stomach, which is explained by the loss of amylases’ activity in an acidic environment.

Digestion in the stomach cavity

The process of digestion in the human body occurs under the influence of gastric juice containing lipase, which is capable of breaking down fats. In this case, great importance is given to the hydrochloric acid of gastric juice. Under the influence of hydrochloric acid, the activity of enzymes increases, denaturation and swelling of proteins is caused, and a bactericidal effect is exerted.

The physiology of digestion in the stomach is that food enriched with carbohydrates, which remains in the stomach for about two hours, undergoes an evacuation process faster than food containing proteins or fats, which lingers in the stomach for 8-10 hours.

Food that is mixed with gastric juice and partially digested, being in a liquid or semi-liquid consistency, passes into the small intestine in small portions at simultaneous intervals. In which department does the digestion process still take place in the human body?

Digestive department - small intestine

Digestion in the small intestine, into which the bolus of food enters from the stomach, has the most important place, from the point of view of the biochemistry of the absorption of substances.

In this section, the intestinal juice consists of an alkaline environment due to the arrival of bile, pancreatic juice and secretions of the intestinal walls into the small intestine. The digestive process in the small intestine does not go quickly for everyone. This is facilitated by the presence of an insufficient amount of the lactase enzyme, which hydrolyzes milk sugar, which is associated with the indigestibility of whole milk. During the digestion process, more than 20 enzymes are consumed in this part of the human body, for example, peptidases, nucleases, amylase, lactase, sucrose, etc.

The activity of this process in the small intestine depends on the three intersecting sections of which it consists - the duodenum, jejunum and ileum. Bile formed in the liver enters the duodenum. Here food is digested thanks to the pancreatic juice and bile that act on it. This colorless liquid contains enzymes that promote the breakdown of proteins and polypeptides: trypsin, chymotrypsin, elastase, carboxypeptidase and aminopeptidase.

Role of the liver

An important role in the process of digestion in the human body (we will briefly mention this) is played by the liver, in which bile is formed. The peculiarity of the digestive process in the small intestine is due to the assistance of bile in emulsifying fats, absorbing triglycerides, activating lipase, also helps stimulate peristalsis, inactivate pepsin in the duodenum, has a bactericidal and bacteriostatic effect, increases hydrolysis and absorption of proteins and carbohydrates.

Bile does not contain digestive enzymes, but is important in the dissolution and absorption of fats and fat-soluble vitamins. If bile is not produced enough or is secreted into the intestines, then the processes of digestion and absorption of fats are disrupted, as well as an increase in their excretion in their original form with feces.

What happens in the absence of a gallbladder?

The person is left without the so-called small sac, in which bile was previously deposited “in reserve.”

Bile is needed in the duodenum only if there is food in it. And this is not a constant process, only during the period after eating. After some time, the duodenum is emptied. Accordingly, the need for bile disappears.

However, the work of the liver does not stop there; it continues to produce bile. It is for this purpose that nature created the gallbladder, so that the bile secreted in the intervals between meals does not deteriorate and is stored until the need for it arises.

And here the question arises about the absence of this “bile storage”. As it turns out, a person can do without a gallbladder. If the operation is performed on time and other diseases associated with the digestive organs are not provoked, then the absence of a gallbladder in the body is easily tolerated. The timing of the digestion process in the human body is of interest to many.

After surgery, bile can only be stored in the bile ducts. After bile is produced by liver cells, it is released into the ducts, from where it is easily and continuously sent to the duodenum. Moreover, this does not depend on whether the food is taken or not. It follows that after the gallbladder has been removed, food must be taken frequently and in small portions for the first time. This is explained by the fact that there is not enough bile to process large portions of bile. After all, there is no longer a place for its accumulation, but it enters the intestine continuously, albeit in small quantities.

It often takes time for the body to learn to function without a gallbladder and to find the necessary place to store bile. This is how the digestion process works in the human body without a gallbladder.

Digestive department - large intestine

The remains of undigested food move into the large intestine and remain there for approximately 10 to 15 hours. Here the following digestive processes take place in the intestines: absorption of water and microbial metabolization of nutrients.

In digestion, food plays a huge role, which includes indigestible biochemical components: fiber, hemicellulose, lignin, gums, resins, waxes.

The structure of food affects the speed of absorption in the small intestine and the time of movement through the gastrointestinal tract.

Some of the dietary fiber that is not broken down by enzymes belonging to the gastrointestinal tract is destroyed by microflora.

The large intestine is the place of formation of feces, which includes: undigested food debris, mucus, dead cells of the mucous membrane and microbes that continuously multiply in the intestines and which cause the processes of fermentation and gas formation. How long does the digestion process in the human body last? This is a common question.

Breakdown and absorption of substances

The absorption process occurs throughout the entire digestive tract, which is covered with hairs. On 1 square millimeter of mucous membrane there are about 30-40 villi.

In order for the process of absorption of substances that dissolve in fats, or rather fat-soluble vitamins, to occur, fats and bile must be present in the intestines.

Absorption of water-soluble products such as amino acids, monosaccharides, mineral ions occurs with the participation of blood capillaries.

In a healthy person, the entire digestion process takes from 24 to 36 hours.

This is how long the digestion process in the human body lasts.

"Anatomy of the Digestive System"

Topic study plan:

General data on the structure of the organs of the digestive system.

Oral cavity and its contents.

The structure of the pharynx. Lymphoepithelial ring. Esophagus.

The structure of the stomach.

Small and large intestine, structural features.

The structure of the liver. Gallbladder.

Pancreas.

General information about the peritoneum.

General data on the structure of the organs of the digestive system.

The digestive system is a complex of organs whose function is to mechanically and chemically process food substances, absorb processed substances and eliminate the remaining undigested parts of food. The organs of the digestive system include the oral cavity with its contents, pharynx, esophagus, stomach, small intestine, large intestine, liver and pancreas.

Oral cavity and its contents.

The oral cavity is divided into the vestibule of the mouth and the oral cavity itself. The vestibule of the mouth is the space located between the lips and cheeks on the outside, and the gums and teeth on the inside. Through the oral opening, the vestibule of the mouth opens outward. The oral cavity itself is limited respectively in front - by the teeth and gums, in the back - it communicates with the pharynx using the pharynx, above - by the hard and soft palate, below - by the tongue and the diaphragm of the oral cavity.

IN The oral cavity contains the teeth, tongue and the ducts of the salivary glands open. During life, a person has 20 primary and 32 permanent teeth. They are divided into incisors (2), canines (1), small molars (2), large molars (2-3); formula of milk teeth: 2 1 0 2, that is, there are no small molars. The formula for permanent teeth is: 2 1 2 3. Each tooth has a crown, a neck and a root. The crown is covered on the outside with enamel, the root is covered with cement, and the entire tooth consists of dentin, inside of which there is a cavity filled with pulp (contains nerves, blood vessels, connective tissue). Mechanical processing of food occurs with the help of teeth. The tongue is a muscular organ. It participates in the processes of formation of the food bolus and the acts of swallowing and speech formation; Due to the presence of specific nerve endings on its mucous membrane, the tongue is also an organ of taste and touch. The basis of the tongue is made up of striated voluntary muscles. They are divided into two groups: the intrinsic muscles of the tongue (superior and inferior longitudinal, vertical, transverse) and skeletal muscles (styloglossus, genioglossus and hypoglossus muscles). The contraction of these muscles makes the tongue mobile, easily changing shape. The tongue is divided into body, apex, root, upper surface (back) and lower surface. The outside of the tongue is covered with a mucous membrane. On the upper surface of the tongue there are papillae: mushroom-shaped, groove-shaped, conical, filiform and leaf-shaped. With the help of these
structures perceive the taste of food taken, its temperature and consistency. On the lower surface of the tongue there is a frenulum, on either side of which there is a hyoid caruncle. A duct common to the sublingual and submandibular salivary glands opens in them. Additionally, in the thickness of the mucous membrane, oral cavity and tongue, there are a large number of small salivary glands. At the vestibule of the oral cavity, the duct of the third major salivary gland, the parotid gland, opens. The orifices of the duct open on the mucous membrane of the cheek at the level of the upper second molar. The salivary glands differ from each other in structure and secretion. Thus, the parotid gland is alveolar in structure and serous in secretion; submandibular gland, respectively, to alveolar-tubular and mixed; sublingual - to the alveolar-tubular and mucous membranes.

The structure of the pharynx. Lymphoepithelial ring. Esophagus.

G tray - a hollow muscular organ. The pharynx cavity is divided into three parts: nasal, oral and laryngeal. The nasal part of the pharynx communicates with the nasal cavity through the choanae, and with the middle ear cavity through the auditory tube; the oral part of the pharynx communicates with the oral cavity through the pharynx, and the laryngeal part communicates with the vestibule of the larynx, and then passes into the esophagus. The function of the nasal part of the pharynx is respiratory, because serves only to conduct air; the oral part of the pharynx is mixed - both respiratory and digestive, because conducts both air and the food bolus, and the laryngeal part is only digestive, because carries only food. The wall of the pharynx consists of mucous, fibrous, muscular and connective tissue membranes. The muscular coat is represented by striated muscles: three pairs of muscles that compress the pharynx and two pairs of muscles that elevate the pharynx. A number of accumulations of lymphoid tissue are focally located in the pharynx. So, in the area of ​​​​its arch lies the pharyngeal tonsil, in the place where the auditory tubes open - the tubal tonsils, at the root of the tongue the lingual tonsil is localized and between the arches of the soft palate there are two palatine tonsils. The pharyngeal, palatine, lingual and tubal tonsils form the pharyngeal lymphoepithelial ring of Pirogov.

The esophagus is a tube flattened from front to back, 23-25 ​​cm long. It begins at the level of the VI cervical vertebra and passes into the stomach at the level of the XI thoracic vertebra. It has three parts - cervical, thoracic and abdominal. Along the esophagus there are five narrowings and two expansions. Three constrictions are anatomical and are preserved on the corpse. These are pharyngeal (at the junction of the pharynx with the esophagus), bronchial (at the level of the trachea bifurcation) and diaphragmatic (when the esophagus passes through the diaphragm). Two narrowings are physiological, they are expressed only in a living person. Aortic (in the area of ​​the aorta) and cardiac (at the transition of the esophagus to the stomach) narrowing. The dilations are located above and below the diaphragmatic constriction. The wall of the esophagus consists of three membranes (mucosal, muscular and connective tissue). The muscular coat has a peculiarity: in the upper part it consists of striated muscle tissue and is gradually replaced by smooth muscle tissue. The middle and lower thirds of the esophagus contain only smooth muscle cells.

The structure of the stomach.

AND The stomach is a muscular hollow organ, which has a cardiac part, fornix, body, and pyloric part. The stomach has an inlet (cardial) and an outlet (pylorus), anterior and posterior walls, two curvatures - greater and lesser. The wall of the stomach consists of four membranes: mucosa, submucosa, muscular and serous. The mucous membrane is lined with single-layer epithelium and has numerous tubular gastric glands. There are three types of glands: cardiac, gastric and pyloric. They consist of three types of cells: main cells (produce pepsinogen), parietal cells (produce hydrochloric acid) and accessory cells (produce mucin). The submucosa of the stomach is quite well developed, which contributes to the formation of numerous folds on the mucous membrane. This ensures close contact of food with the mucous membrane and increases the area of ​​absorption of nutrients into the blood. The muscular lining of the stomach is represented by non-striated muscle tissue and consists of three layers: outer - longitudinal, middle - circular and inner - oblique. The most pronounced circular layer is at the border between the pylorus and the duodenum and forms a muscular ring - the pyloric sphincter. The outermost layer of the stomach wall is formed by the serosa, which is part of the peritoneum. The stomach is located in the abdominal cavity. Under the influence of gastric juice, food is digested in the stomach, all enzymes of which act only in an acidic environment (pH = 1.5-2.0), and this is created by the presence of hydrochloric acid up to 0.5%. Food stays in the stomach for 4 to 10 hours, and in that part of the bolus of food that has not yet been saturated with gastric juice, salivary enzymes break down carbohydrates, but this is a trace reaction. In the stomach, complex proteins are broken down into simpler ones of varying degrees of complexity under the action of pepsin, which is formed from pepsinogen as a result of activation with hydrochloric acid. Chymosin curdles milk proteins. Lipase breaks down emulsified milk fat. The formation and secretion of gastric juice is regulated by the neurohumoral pathway. I.P. Pavlov identified two phases - reflex and neurohumoral. In the first phase, secretion occurs upon stimulation of the receptors of smell, hearing, vision, during eating and during swallowing. In the second phase, gastric secretion is associated with food irritation of the receptors of the gastric mucosa and stimulation of the brain centers of digestion.

Humoral regulation occurs due to the appearance in the blood of stomach hormones, products of protein digestion and various minerals. The nature of secretion depends on the quality and quantity of food, on the emotional state and health and continues as long as there is food in the stomach. Contractions in the walls of the stomach mix food with gastric juice, which promotes better digestion and transformation into a liquid paste. The passage of food from the stomach to the duodenum occurs in doses, and is dosed by the pyloric sphincter through neurohumoral regulation. The sphincter opens when the environment of food leaving the stomach becomes neutral or alkaline, and after the release of a new portion with an acidic reaction, the sphincter contracts and stops the passage of food.

Small and large intestine, structural features.

The small intestine begins at the pylorus of the stomach and ends at the beginning of the large intestine. The length of the small intestine in a living person is about 3 m, its diameter ranges from 2.5 to 5 cm. The small intestine is divided into duodenum, jejunum and ileum. The duodenum is short - 27-30 cm. Most of the intestine lies to the right of the bodies of the I-II lumbar vertebrae in the region of the posterior wall of the abdominal cavity and for its greater extent is located retroperitoneally, i.e. covered by peritoneum only in front. The common bile duct and the pancreatic duct flow into the intestine, which, before entering the intestine, connect and open with a common opening on the major duodenal papilla. The duodenum consists of four parts: upper, descending, horizontal and ascending parts, and has the shape of a horseshoe that covers the head of the pancreas.

T The colon and ileum have significant mobility, since they are covered with peritoneum on all sides and are attached to the posterior wall of the abdominal cavity through the mesentery. The wall of the small intestine consists of the mucosa, submucosa, muscularis and serosa. A distinctive feature of the small intestine is the presence of villi in the mucous membrane covering its surface. In addition to villi, the mucous membrane of the small intestine has numerous circular folds, due to which the area of ​​​​absorption of nutrients increases. The small intestine has its own lymphatic apparatus, which serves to neutralize microorganisms and harmful substances. It is represented by single and group lymphatic follicles. The muscular layer of the small intestine consists of two layers: the outer - longitudinal and the inner - circular. Thanks to the muscle layers in the intestine, peristaltic and pendulum-like movements are constantly carried out, which contribute to the mixing of the food mass. The reaction of the intestinal environment is alkaline; this is where the main digestion occurs. The enzyme of the intestinal glands, enterokinase, converts inactive trypsinogen into active trypsin, which, together with chymotrypsin, breaks down proteins into amino acids. Lipase, activated under the influence of bile, breaks down fats into glycerol and fatty acids. Amylase, maltase, lactase break down carbohydrates into glucose (monosaccharides). In the jejunum and ileum, food digestion ends and the resulting products of digested food are absorbed. For absorption, the mucous membrane has a huge number of microvilli. On the outside, the villi are covered with epithelial cells, in the center there is a lymphatic sinus, and along the periphery there are blood capillaries 18-20 per 1 mm 2. Amino acids and monosaccharides are absorbed into the blood of the capillaries of the villi. Glycerol and fatty acids are absorbed mainly into the lymph and then enter the blood. In the small intestine, food is almost completely digested and absorbed. Undigested residues enter the large intestine, mainly plant fiber, 50% unchanged.

The large intestine is divided into a number of parts: the cecum with the appendix, the ascending colon, the transverse colon, the descending colon, the sigmoid colon and the rectum. The length of the large intestine ranges from 1 to 1.5 m, its diameter ranges from 4 to 8 cm. The large intestine has a number of distinctive features from the small intestine: the walls have special longitudinal muscle cords - ribbons; swellings and omental processes. The wall of the colon consists of the mucosa, submucosa, muscularis and serosa. The mucous membrane does not have villi, but has semilunar folds. The latter increase the absorption surface of the mucous membrane; in addition, the mucous membrane contains a large number of group lymphatic follicles. A feature of the structure of the intestinal wall is the location of the muscular layer. The muscular layer consists of an outer - longitudinal and inner - circular layers. The circular layer of all parts of the intestine is continuous, and the longitudinal layer is divided into three narrow strips. These bands begin at the origin of the appendix from the cecum and extend to the beginning of the rectum. In this case, the ribbons of the longitudinal muscle layer are much shorter than the length of the intestine, which leads to the formation of swellings separated from each other by grooves. Each groove corresponds to a semilunar fold on the inner surface of the intestine. The serous membrane covering the large intestine forms protrusions filled with adipose tissue - omental processes. The large intestine is separated from the small intestine by the ileocecal sphincter. The function of the large intestine is to absorb water, ferment carbohydrates, putrefy proteins and form feces. Peristaltic and pendulum-like movements occur in the large intestine. The large intestine does not have villi, and the glands produce a small amount of juice. Bacteria located in the large intestine contribute to the breakdown of fiber and the synthesis of a number of vitamins. Putrefactive bacteria from protein breakdown products can form toxic substances - indole, skatole, phenol.

In the large intestine, water, rotting and fermentation products are absorbed, as well as the formation of feces. Blood from the intestines passes through the liver, where nutrients undergo a series of transformations and toxic substances are neutralized.

The structure of the liver. Gallbladder.

P
The liver is the largest gland in the body (its weight is about 1.5 kg). The functions of the liver are diverse: antitoxic function (neutralization of phenol, indole and other decay products that are absorbed from the lumen of the colon), participates in protein metabolism, the synthesis of phospholipids, blood proteins, converts ammonia into urea, cholesterol into bile acids, is a blood depot and In the embryonic period, the liver has a hematopoietic function. In the liver, glucose is converted into glycogen, which is stored in the liver cells and released into the blood as needed. The liver cells also produce bile, which flows through the bile ducts into the lumen of the duodenum. Excess bile accumulates in the gallbladder. Up to 1200 ml of bile is formed and secreted per day. When digestion does not occur, bile accumulates in the gallbladder and enters the intestine as needed, depending on the availability and composition of food taken. The color of bile is yellow-brown and is caused by the pigment bilirubin, which is formed as a result of the breakdown of hemoglobin. Bile emulsifies fats, facilitating their breakdown, and also activates the digestive enzymes of the intestines. The liver is located in the abdominal cavity, mainly in the right hypochondrium. The liver has two surfaces: diaphragmatic and visceral. Divided into right and left lobes. The gallbladder lies on the lower surface of the liver. In the posterior section, the inferior vena cava passes through the liver. The transverse groove on the lower surface of the liver is called the porta hepatis. The gates of the liver include the proper hepatic artery, the portal vein and the accompanying nerves. The common hepatic duct and lymphatic vessels emerge from the porta hepatis. The structural unit of the liver is hepatic lobule, which has the shape of a prism and consists of numerous liver cells that form crossbars - trabeculae. The trabeculae are oriented radially - from the periphery of the lobule to the center, where the central vein lies. Along the edges of the prism lie the interlobular artery, vein and bile duct, which form hepatic triad. In the thickness of the trabeculae, which are formed by two rows of liver cells, there are bile ducts into which bile is produced. Through these ducts it enters the interlobular bile ducts. Bile leaves the liver through the common hepatic duct. As stated above, the reservoir for the accumulation of bile is gallbladder. The gallbladder is a hollow muscular organ in which bile accumulates. It distinguishes between the bottom, body and neck. The cystic duct arises from the cervix and joins the common hepatic duct to form the common bile duct. The wall of the gallbladder consists of mucous, muscular and serous membranes.

Pancreas.

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The pancreas is not only a large exocrine gland, but also an endocrine gland. It consists of a head, body, and tail. The pancreas is located so that its head is covered by the duodenum (at the level of the I-II lumbar vertebrae, to the right of them), and the body and tail extend from the head to the left and up. The tail of the gland is directed towards the spleen. The length of the pancreas is 12-15 cm. Inside the gland, along its length there is a pancreatic duct, into which ducts from the lobules of the gland flow. The duct of the gland connects with the bile duct and opens with a common opening into the duodenum at the top of the major papilla. Sometimes an accessory duct is found. Most of the substance of the pancreas consists of alveolar tubular glands, which produce pancreatic juice. The lobules consist of glandular cells where digestive enzymes are synthesized - trypsin, chymotrypsin, lipase, amylase, maltase, lactase, etc., which enter the duodenum as part of the pancreatic juice through the duct. Pancreatic juice is colorless, transparent, has an alkaline reaction, about 1 liter is produced per day. It is involved in the breakdown of proteins, fats and carbohydrates. In addition, the substance of the gland contains specially designed islets of Langerhans, which release hormones into the blood - insulin (reduces blood glucose) and glucagon (increases blood glucose). The pancreas lies retroperitoneally (extraperitoneal position).

The role of I.P. Pavlova in the study of the functions of the digestive organs. Before Pavlov, the effect of individual enzymes and juices on many foods was known, but it was not clear how these processes occurred in the body. A detailed study of the secretion of glands became possible after the introduction of the fistula technique. For the first time, the operation of gastric fistula in animals was performed by Russian surgeon V.A. Basov in 1842. A fistula is a connection between organs and the external environment or other organs. I.P. Pavlov and his colleagues improved and applied new operations to create fistulas of the salivary glands, stomach, and intestines in animals to obtain digestive juices and determine the activity of these organs. They found that the salivary glands are excited reflexively. Food irritates the receptors located in the oral mucosa and the excitation from them travels through the centripetal nerves to the medulla oblongata, where the center of salivation is located. From this center, along the centrifugal nerves, excitation reaches the salivary glands and causes the formation and secretion of saliva. This is an innate unconditioned reflex.

Along with unconditioned salivary reflexes, there are conditioned salivary reflexes in response to visual, auditory, olfactory and other stimuli. For example, the smell of food or a sight causes salivation.

To obtain pure stomach juice I.P. Pavlov proposed the method of imaginary feeding. The esophagus in the neck of a dog with a gastric fistula was cut and the cut ends were sutured to the skin. After such an operation, food enters the stomach and falls out through the opening of the esophagus and the animal can eat for hours without being satisfied. These experiments make it possible to study the influence of reflexes from receptors in the oral mucosa on the gastric glands. But this surgical technique cannot completely reproduce the conditions and processes in the stomach, since there is no food in it. To study the processes of digestion in the stomach I.P. Pavlov performed an operation on the so-called small ventricle. The small ventricle was cut out from the stomach wall so that neither the nerves nor the vessels connecting it to the large one were damaged. The small ventricle represents a section of the large one, but its cavity is isolated from the latter by a wall of fused mucous membrane, so that food digested in the large ventricle cannot enter the small one. With the help of a fistula, the small ventricle communicates with the external environment and the function of the stomach was studied by secreting juice. Works by I.P. Pavlov’s study of the digestive organs formed the basis for the treatment of these organs, the therapeutic nutrition system and the dietary regime of a healthy person.

Suction is a complex physiological process by which nutrients pass through the layer of cells in the wall of the digestive tract into the blood and lymph. Absorption occurs most intensively in the jejunum and ileum. Monosaccharides, minerals, water and alcohol are absorbed in the stomach; mainly water, as well as some salts and monosaccharides, are absorbed in the colon. Medicinal substances, depending on their chemical and physicochemical properties, as well as on a particular dosage form, can be absorbed in all parts of the digestive tract. The absorption process is ensured by filtration, diffusion and active transport, regardless of the difference in the concentration of dissolved substances. The motor activity of the villi is of great importance. The total surface of the mucous membrane of the small intestine due to the villi is 500 m2. Amino acids and carbohydrates are absorbed into the venous part of the capillary network of the villi and enter the portal vein, passing through the liver and entering the general circulation. Fats and their breakdown products enter the lymphatic vessels of the villi. In the epithelium of the villi, the synthesis of neutral fats occurs, which in the form of tiny droplets enter the lymphatic capillaries, and from there with the lymph into the blood.

Suction water diffusion begins in the stomach and occurs intensively in the small and large intestines. A person consumes about 2 liters of water per day. In addition, about 1 liter of saliva, 1.5-2.0 liters of gastric juice, about one liter of pancreatic juice, 0.5-0.7 liters of bile, 1-2 liters of intestinal juice enter the gastrointestinal tract. In just one day, 6-8 liters of liquid enter the intestines, and 150 ml are excreted in feces. The rest of the water is absorbed into the blood. Minerals dissolved in water are absorbed mainly in the small intestine by active transport.

HYGIENIC CONDITIONS FOR NORMAL DIGESTION

Diseases of the digestive system are quite common. The most common are gastritis, gastric and duodenal ulcers, enteritis, colitis and cholelithiasis.

Gastritis is an inflammation of the stomach lining. It occurs under the influence of various pathogenic factors: physical, chemical, mechanical, thermal and bacterial agents. Violation of the diet and quality of nutrition is of great importance in the development of the disease. With gastritis, secretion is disrupted and the acidity of gastric juice changes. Stomach dysfunction with gastritis often affects the activity of other organs of the digestive system. Gastritis is often accompanied by inflammation of the small intestine (enteritis), inflammation of the large intestine (colitis) and inflammation of the gallbladder (cholecystitis). Peptic ulcer disease is characterized by the formation of non-healing ulcers in the stomach or duodenum. Peptic ulcer disease is not a local process, but the suffering of the whole organism. Neuropsychic trauma, increased excitability of the receptor apparatus of the gastrointestinal tract, and reduced resistance of the mucous membrane to the digestive action of gastric juice play a role in the development of the disease. A certain role in the development of peptic ulcer is given to hereditary factors.

Serious diseases such as typhoid fever, dysentery, cholera, polio and others can be transmitted through the digestive tract. These diseases usually occur due to poor water supply, consumption of unwashed vegetables and fruits, which transmit pathogenic microbes, and poor personal hygiene.

Regulation of digestive processes. Physiological studies of digestion were carried out by I.P. Pavlov. The entire series of works he published is called “Works on the physiology of digestion,” which included such as “On reflex inhibition of salivation” (1878), “On a surgical method for studying the secretory phenomena of the stomach” (1894), “On the digestive center” ( 1911) etc.

Before Pavlov's work, only unconditioned reflexes were known, but Pavlov established the enormous importance of conditioned reflexes. He found that gastric juice is secreted in two phases. The first begins as a result of food irritation of the receptors of the oral cavity and pharynx, as well as visual and olfactory receptors (the sight and smell of food). The excitation that arises in the receptors travels through the centripetal nerves to the digestive center located in the medulla oblongata, and from there through the centrifugal nerves to the salivary glands and stomach glands. Juice secretion in response to irritation of the receptors of the pharynx and mouth is an unconditioned reflex, and juice secretion in response to irritation of the olfactory and taste receptors is a conditioned reflex. The second phase of secretion is caused by mechanical and chemical irritations. In this case, acetylcholine, hydrochloric acid, gastrin, as well as food components and protein digestion products are irritants. You should have an understanding of the concepts of “hunger” and “appetite”. Hunger is a condition that requires eating a certain amount of food to eliminate. Appetite is characterized by a selective attitude towards the quality of the food offered. It is regulated by the cerebral cortex and depends on numerous mental factors.

One of the most important components of the human body is its digestive organ system. This totality is thought out and organized by nature in such a way that its owner can extract from the food consumed everything that is necessary for normal life activities. And at the same time, such “magic” mechanisms operate in the digestive system that protect us from infections, neutralize poisons and even allow us to independently synthesize important vitamins. Considering the importance of this complex of organs, it needs to be protected.

Let's consider what functions are, and we won't leave them without attention. You will also learn about what you must do to avoid gastrointestinal diseases.

What organs are included in the digestive system?

The digestive system consists of the following organs and sections:

• the oral cavity with its salivary glands;
• pharynx;
• esophagus area;
• stomach;
• small and large intestines;
• liver;
• pancreas.

If you look at the structure of this organ system, you can note that the digestive tract is a tube 7-9 m long. Some large glands are located outside the walls of the system and communicate with it.

The peculiarity of this set of organs is that they are laid out very compactly. The length of the tract from the mouth to the anus is up to 900 cm, but the ability of the muscles of the digestive tract to form loops and bends helped to fit them into the human body. However, our task is not only to list the organs of the digestive system. We will carefully study all the processes occurring in each section of the gastrointestinal tract.

General scheme of the gastrointestinal tract

The pharynx and esophagus have a virtually straight direction.

Now let's briefly look at the sequence of food passage through the organs of the digestive system. Nutrient components enter the human body through the mouth.

Next, the mass follows into the pharynx, where the digestive tract and respiratory organs intersect. After this section, the food bolus is directed down the esophagus. Chewed food and moistened with saliva enters the stomach. In the abdominal region there are organs of the final segment of the esophagus: the stomach, small, blind, colon, as well as glands: the liver and pancreas.

The rectum is located in the pelvic area. Food stays in the stomach cavity for different times depending on the type of food, but this period does not exceed several hours. At this time, the so-called food is released into the cavity of the organ, the food becomes liquid, it is mixed and digested. Moving further, the mass enters Here, the activity of enzymes ensures further dissolution of nutritional substances into simple compounds, which are easily absorbed into the bloodstream and lymph.

Next, the residual masses move into the large intestine, where water is absorbed and feces are formed. Essentially, these are substances that are not digested and cannot be absorbed into the blood and lymph. They are removed into the external environment through the anus.

Why does a person saliva?

On the oral mucosa, from which the sequence of food passage through the organs of the digestive system begins, there are large and small ones. Large ones are those located near the ears, under the jaws and under the tongue. The last two types of salivary glands produce a mixed secretion: they secrete both saliva and water. The glands near the ears are capable of producing only mucus. Drooling can be quite intense. For example, when drinking lemon juice, up to 7.5 ml per minute can be released.

Saliva is mostly water, but it contains enzymes: maltase and amylase. These enzymes start the digestion process already in the oral cavity: starch is converted by amylase into maltose, which is further broken down by maltase into glucose. Food is in the mouth for a short time - no more than 20 seconds, and during this time the starch simply does not have time to dissolve completely. Saliva usually has either a neutral or slightly alkaline reaction. This liquid medium also contains a special protein, lysozyme, which has bactericidal properties.

We follow the esophagus

The anatomy of the digestive system calls the esophagus the next organ of the gastrointestinal tract after the mouth and pharynx. If we examine its wall in cross-section, we can clearly distinguish three layers. The middle one is muscular and is capable of contraction. This quality allows food to move from the pharynx to the stomach. The musculature of the esophagus produces wave-like contractions that extend from the top of the organ along its entire length. When a bolus of food passes along this tube, the entrance sphincter opens into the stomach.

This muscle holds food in the stomach and prevents it from moving in the opposite direction. In some cases, the locking sphincter weakens, and digested masses can be thrown into the esophagus. Reflux occurs and the person feels heartburn.

The stomach and the secrets of digestion

We continue to study the order of the organs of the digestive system. Following the esophagus is the stomach. Its localization is the left hypochondrium in the epigastric region. This organ is nothing more than an extension of the digestive tract with pronounced wall musculature.

The shape and size of the stomach directly depend on its contents. An empty organ has a length of up to 20 cm, the distance between the walls is 7-8 cm. If the stomach is filled moderately, then its length will become about 25 cm and width - up to 12 cm. The capacity of the organ can also vary depending on the degree of its fullness and varies from 1.5 l to 4 l. When a person swallows, the stomach muscles relax, and this effect lasts until the end of the meal. But even when the meal is over, the stomach muscles are in a state of activity. Food is ground, its mechanical and chemical processing occurs through muscle movement. Digested food moves to the small intestine.

The inside of the stomach is lined with many folds in which the glands are located. Their task is to secrete as many digestive juices as possible. Stomach cells produce enzymes, hydrochloric acid and mucoid secretions. The food bolus is saturated with all these substances, crushed and mixed. Muscles, contracting, promote digestion.

What is gastric juice?

Gastric juice is a colorless liquid with an acidic reaction, which is due to the presence of hydrochloric acid. It contains three main groups of enzymes:

• proteases (mainly pepsin) break down proteins into polypeptide molecules;
• lipases, which act on fat molecules, converting them into fatty acids and glycerol (only emulsified cow's milk fat is broken down in the stomach);
• salivary amylases continue to work on breaking down complex carbohydrates into simple sugars (as the bolus of food is completely saturated with acidic gastric juice, amylolytic enzymes are inactivated).

Hydrochloric acid is a very important element of digestive secretion, as it activates the enzyme pepsin, prepares protein molecules for breakdown, curdles milk and neutralizes all microorganisms. The secretion of gastric juice occurs mainly when eating and continues for 4-6 hours. In total, up to 2.5 liters of this liquid are released per day.

An interesting fact is that the quantity and composition of gastric juice depend on the quality of incoming food. The largest amount of secretion is secreted for the digestion of protein substances, the smallest - when a person absorbs fatty foods. In a healthy body, gastric juice contains a fairly large amount of hydrochloric acid; its pH ranges from 1.5-1.8.

Small intestine

When studying the question of which organs are included in the digestive system, the further object of study is the small intestine. This section of the digestive system originates from the gastric pylorus and has a total length of up to 6 meters. It is divided into several sections:

• The duodenum is the shortest and widest section, its length is about 30 cm;
• the jejunum is characterized by a decrease in lumen and a length of up to 2.5 m;
• The ileum is the narrowest part of the thin section, its length is up to 3.5 m.

The small intestine is located in the abdominal cavity in the form of loops. From the frontal part it is covered by the omentum, and on the sides it is limited by the thick digestive tract. The function of the small intestine is to continue the chemical transformations of food components, mix it and further direct it to the thick section.

The wall of this organ has a typical structure for all components of the gastrointestinal tract and consists of the following elements:

• mucous layer;
• submucosal tissue with accumulations of nerves, glands, lymphatic and blood vessels;
• muscle tissue, which consists of outer longitudinal and inner circular layers, and between them there is a layer of connective tissue with nerves and blood vessels (the muscle layer is responsible for mixing and moving digested food along the system);
• The serous membrane is smooth and moisturized, it prevents friction between the organs.

Features of digestion in the small intestine

The glands that are part of the intestinal tissue secrete secretions. It protects the mucous membrane from injury and from the activity of digestive enzymes. The mucous tissue forms many folds in a circular direction, and this increases the absorption area. The number of these formations decreases towards the large intestine. From the inside, the mucous membrane of the small intestine is replete with villi and grooves that help digestion.

The duodenum has a slightly alkaline environment, but as stomach contents enter it, the pH decreases. The pancreas has a duct into this zone, and its secretion alkalizes the food bolus, the environment of which becomes neutral. Thus, gastric juice enzymes are inactivated here.

A few words about the digestive glands

Has ducts of endocrine glands. The pancreas secretes its juice as a person eats, and its amount depends on the composition of the food. A protein diet provokes the greatest secretion, while fats cause the opposite effect. In just one day, the pancreas produces up to 2.5 liters of juice.

The gallbladder also secretes its secretion into the small intestine. Already 5 minutes after the start of the meal, bile begins to be actively produced, which activates all the enzymes of intestinal juice. This secretion also enhances the motor functions of the gastrointestinal tract, intensifies the mixing and movement of food. In the duodenum, about half of the proteins and sugars that come with food, as well as a small part of the fats, are digested. In the small intestine, the enzymatic breakdown of organic compounds continues, but less intensely, and parietal absorption predominates. This process occurs most intensively 1-2 hours after eating. It is more effective than the similar stage in the stomach.

The large intestine is the final station of digestion

This section of the gastrointestinal tract is the final one, its length is about 2 m. The names of the organs of the digestive system take into account their anatomical features, and it is logically clear that this section has the largest lumen. The width of the large intestine decreases from 7 to 4 cm at the descending colon. The following zones are distinguished in this section of the digestive tract:

• the cecum, which has a vermiform appendix, or appendix;
• ascending colon;
• transverse colon;
• descending colon;
• sigmoid colon;
• straight section ending in the anus.

Digested food passes from the small intestine to the large intestine through a small opening in the form of a slit located horizontally. There is a kind of valve with a sphincter in the form of lips, which prevents the contents of the blind section from entering in the opposite direction.

What processes occur in the large intestine?

If the entire process of digesting food lasts from one to three hours, then most of the time is spent on the lump remaining in the large intestine. It accumulates contents, absorbs necessary substances and water, moves along the tract, forms and removes feces. The physiological norm is considered to be the entry of digested food into the large intestine 3-3.5 hours after a meal. This section is filled throughout the day, followed by its complete emptying in 48-72 hours.

In the large intestine, glucose, amino acids, vitamins and other substances produced by bacteria living in this section are absorbed, as well as the vast majority (95%) of water and various electrolytes.

Inhabitants of the gastrointestinal tract

Almost all organs and parts of the digestive system are inhabited by microorganisms. Only the stomach is relatively sterile (on an empty stomach) due to the acidic environment. The largest number of bacteria is found in the large intestine - up to 10 billion/1 g of feces. The normal microflora of the thick gastrointestinal tract is called eubiosis and plays a huge role in human life:

• prevents the development of pathogenic microorganisms;
• synthesis of vitamins B and K, enzymes, hormones and other substances beneficial to humans;
• breakdown of cellulose, hemicellulose and pectins.

The quality and quantity of microflora in each person is unique and is regulated by both external and internal factors.

Take care of your health!

Like any part of the human body, the digestive organ system can be susceptible to various diseases. They are often associated with the ingress of pathogenic microorganisms from outside. However, if a person is healthy and his stomach works without failures, then everyone is doomed to death in an acidic environment. If for a number of reasons this organ functions abnormally, then almost any infection can develop and lead to serious consequences, such as cancer of the digestive system. It all starts small: poor nutrition, lack of alcohol and fatty foods in the diet, smoking, stress, unbalanced diets, poor environment and other unfavorable factors gradually destroy our body and provoke the development of diseases.

The digestive system of organs is especially susceptible to destructive influences from the outside. Therefore, do not forget to undergo a medical examination in a timely manner and consult a doctor if there are any disruptions in the normal functioning of the body.

The state of our health depends not only on what food we eat, but also on the work of those organs that digest this food and deliver it to every cell of our body.

The digestive system begins with the oral cavity, followed by the pharynx, then the esophagus, and finally the core of the digestive system - the gastrointestinal tract.

Oral cavity is the first section of the digestive system, therefore, the entire further process of digestion depends on how well and correctly all the processes of initial food processing proceed in it. It is in the oral cavity that the taste of food is determined; here it is chewed and moistened with saliva.

Pharynx follows the oral cavity and is a funnel-shaped canal lined with mucous membrane. The respiratory and digestive tracts intersect in it, the activity of which must be clearly regulated by the body (it’s not for nothing that they say when a person chokes that food has gone “down the wrong throat”).

Esophagus It is a cylindrical tube located between the pharynx and stomach. Through it, food enters the stomach. The esophagus, like the pharynx, is lined with a mucous membrane in which there are special glands that produce a secretion that moistens food as it passes through the esophagus into the stomach. The total length of the esophagus is about 25 cm. In a calm state, the esophagus has a folded shape, but it has the ability to lengthen.

Stomach- one of the main components of the digestive tract. The size of the stomach depends on its fullness and ranges from approximately 1 to 1.5 liters. It performs a number of important functions, which include: direct digestive, protective, excretory. In addition, processes associated with the formation of hemoglobin occur in the stomach. It is lined with a mucous membrane, which contains a mass of digestive glands that secrete gastric juice. Here the food mass is saturated with gastric juice and crushed, or rather, the intensive process of its digestion begins.

The main components of gastric juice are: enzymes, hydrochloric acid and mucus. Solid food that enters the stomach can remain in it for up to 5 hours, liquid for up to 2 hours. The components of gastric juice chemically process food entering the stomach, turning it into a partially digested semi-liquid mass, which then enters the duodenum.

Duodenum represents the upper, or first, part of the small intestine. The length of this part of the small intestine is equal to the length of twelve fingers folded together (hence its name). It connects directly to the stomach. Here, in the duodenum, bile from the gallbladder and pancreatic juice enter. The walls of the duodenum also contain a fairly large number of glands that produce an alkaline secretion rich in mucus, which protects the duodenum from the effects of acidic gastric juice entering it.

Small intestine, In addition to the duodenum, it also unites the jejunum and ileum. The small intestine as a whole is approximately 5–6 m long. Almost all basic digestive processes (digestion of food and its absorption) take place in the small intestine. On the inside of the small intestine there are finger-like projections, due to which its surface increases significantly. In humans, the digestive process ends in the small intestine, which is also lined with a mucous membrane very rich in glands that secrete intestinal juice, which contains a fairly large number of enzymes. Enzymes in intestinal juice complete the process of breaking down proteins, fats and carbohydrates. The mass located in the small intestine is mixed due to peristalsis. The food gruel slowly moves through the small intestine, entering the large intestine in small portions.

Colon about twice as thick as a thin one. It consists of the cecum with a vermiform appendix, the colon and rectum. Here, in the large intestine, undigested food remains accumulate, and digestion processes are practically absent. Two main processes occur in the large intestine: the absorption of water and the formation of feces. The rectum serves as a place for the accumulation of feces, which are removed from the body during defecation.

Appendix, as we have already said, it is part of the large intestine and is a short and thin extension of the cecum, about 7-10 cm long. Its functions, as well as the causes of its inflammation, are still not clearly clear to doctors. According to modern data and the opinion of some scientists, the appendix, in the wall of which there are many lymphoid nodules, is one of the organs of the immune system.

But the digestive system, no matter how correctly its individual organs are structured, could not work without certain substances - enzymes, which are produced in the body by special glands. The triggering mechanisms for the digestive system are digestive enzymes, which are proteins that break down large food molecules into smaller ones. The activity of enzymes in our body during the digestion process is aimed at substances such as proteins, fats and carbohydrates, and minerals, water and vitamins are absorbed almost unchanged.

To break down each group of substances, there are specific enzymes: for proteins - proteases, for fats - lipases, for carbohydrates - carbohydrates. The main glands that produce digestive enzymes are the glands of the oral cavity (salivary glands), the glands of the stomach and small intestine, the pancreas and the liver. The main role in this is played by the pancreas, which produces not only digestive enzymes, but also hormones such as insulin and glucagon, which are involved in the regulation of protein, carbohydrate and lipid metabolism.