Principles of the structure of hollow organs. Feet care. The external structure of the liver

Hollow (tubular) organs have multilayered walls.

They distinguish

• mucous,
• muscular
• outer shell.

mucous membrane, tunica mucosa, covers all inner surface hollow organs of the digestive, respiratory and urogenital systems The outer cover of the body passes into the mucous membrane at the openings of the mouth, nose, anus, urethra and vagina.

The mucous membrane is covered with epithelium, under which connective tissue and muscle plates lie. The transport of contents is facilitated by the secretion of mucus by glands located in the mucous membrane.

The mucous membrane carries out mechanical and chemical protection organs from damaging effects. It plays an important role in the biological defense of the body.

In the mucous membrane there are accumulations of lymphoid tissue in the form of lymphatic follicles and more complex tonsils. These entities are included in immune system organism.

The most important function of the mucous membrane is absorption nutrients and liquids.

The mucous membrane is located on the submucosa, telasubmucosa, which consists of loose connective tissue and allows the mucosa to move.

In the submucosa are the main branches of blood vessels that feed the walls of the hollow organ, lymphatic networks and nerve plexuses.

Muscular membrane, tunica muscularis, forms middle part walls of a hollow organ

In most viscera, with the exception of the initial sections of the digestive and respiratory systems, it is built from smooth muscle tissue, which differs from the striated tissue of skeletal muscles in the structure of its cells, and from a functional point of view it has automatism, it contracts involuntarily and more slowly.

In most hollow organs, the muscular membrane has an inner circular and an outer longitudinal layer.

It is established that circular and longitudinal beams have a spiral direction. In the circular layer, the spirals are steep, and in the longitudinal layer, the smooth muscle bundles are curved in the form of very gentle spirals.

If the inner circular layer of the digestive tube contracts, it narrows and somewhat lengthens in this place, and where the longitudinal muscles contract, it shortens and expands slightly. Coordinated contractions of the layers ensure the promotion of the content through a particular tubular system.

In certain places, circular muscle cells are concentrated, forming sphincters that can close the lumen of the organ. Sphincters play a role in regulating the movement of contents from one organ to another (for example, the pyloric sphincter of the stomach) or removing it to the outside (sphincters of the anus, urethra).

outer shell in hollow organs it has a twofold structure. In some, it consists of loose connective tissue - the adventitial membrane, tunica adventitia, others have a character serous membrane, tunica serosa.

Parenchymal organs

Testicle is a parenchymal lobular organ

Deferent tract- paired parenchymal organ

Bulbourethral (Cooper's) glands . These are parenchymal lobular organs.

The principle of the structure of parenchymal organs

The structure of parenchymal organs:

• - a large number of parenchyma, which forms the basis of the body.
• - Compact and in most cases large organs
• - The shape is rounded-elongated and somewhat flattened.
• - They have a gate. Through these gates enter the organ blood vessels, nerves, nerve fibers, and excretory ducts exit. Still at the gate The lymph nodes(names of nodes from the organ: for example, hepatic lymph nodes).
• - All are covered with a serous membrane, which fuses with outer surface and gives them moisture and slipperiness.

Unlike the stroma, which is formed from connective tissue, the parenchyma can be represented different types tissues: hematopoietic (for example, spleen), epithelial (liver, kidneys), nerve cells (ganglions) and etc.

III. Internal organs

1. General principles of the structure of parenchymal and hollow organs. Basic concepts of organ topography: holotopy, dermotopy, skeletopy, syntopy.

Internal organs or entrails(viscera, spldnchna), are located in the head and neck, in the chest, abdominal and pelvic cavities. The viscera are involved in the metabolic functions of the body, its supply with nutrients and energy substances and the excretion of metabolic products.

In accordance with development, features of topography, anatomy, and functions, the insides are divided according to belonging to various systems and apparatuses of organs. There are digestive and respiratory systems, as well as urinary and genital, which are combined into the genitourinary apparatus. The organs of the digestive system are located in the head, neck, chest and abdominal cavities and pelvic cavity. Respiratory organs are located in the head and neck area, chest cavity, urinary organs - in the abdominal and pelvic cavities. In the chest cavity, next to the respiratory and digestive organs, there is the heart - the most important hemodynamic organ, in the abdominal cavity - the spleen (an organ of the immune system). A special position is occupied by the endocrine glands (endocrine glands) located in various areas of the body.

According to their structure, internal organs are divided into parenchymal and hollow (tubular).

Parenchymal organs formed by the parenchyma, the working tissue that performs the specialized functions of the organ, and the connective tissue stroma, which forms the capsule and connective tissue layers (trabeculae) extending from it. Str o m and performs supporting, trophic functions, contains blood and lymphatic vessels, nerves. Parenchymal organs include the pancreas, liver, kidneys, lungs, etc.

hollow organs characterized by the presence of a lumen, have the form of tubes of various diameters. Despite differences in shape and name, hollow internal organs have similar structural features of their walls. In the walls of tubular organs, the following layers-shells are distinguished: the mucous membrane located on the side of the lumen of the organ, the submucosa, the shell). Some tubular organs (trachea, bronchi) have cartilage (cartilaginous skeleton) in their walls.

When characterizing an anatomical object, first of all, its position is noted in relation to the human body as a whole and to parts and areas of the body ( holotopy). To do this, they use such concepts as the ratio of the organ to the median sagittal plane (the organ is located to the left or right of it), to the horizontal (upper or lower floor abdominal cavity) or frontal (closer to the front surface of the body or to the back) plane.

Skeletotopia- another one important characteristic position of the anatomical object. For example, you can describe the upper border of the liver in relation to the ribs and intercostal spaces, the position of the pancreas in relation to the lumbar vertebrae.

syntopia- topographic relation of the organ to neighboring anatomical formations.

2. General principles of development of the digestive system.

The laying of the digestive system is carried out at the early stages of embryogenesis. On the 7-8th day, in the process of development of a fertilized ovum from the endoderm, the primary intestine begins to form in the form of a tube, which on the 12th day differentiates into two parts: the intraembryonic (future digestive tract) and the extraembryonic - the yolk sac. On the early stages formation, the primary intestine is isolated by the oropharyngeal and cloacal membranes, however, already at the 3rd week of intrauterine development, the oropharyngeal membrane melts, and at the 3rd month - the cloacal membrane. Violation of the process of membrane melting leads to developmental anomalies. From the 4th week of embryonic development, the sections of the digestive tract are formed:

derivatives of the foregut - pharynx, esophagus, stomachs, part of the duodenum with the laying of the pancreas and liver;

midgut derivatives - distal part (located farther from the oral membrane) duodenum, jejunum and ileum;

derivatives of the hindgut - all parts of the colon.

The pancreas is laid from the outgrowths of the anterior intestine. In addition to the glandular parenchyma, pancreatic islets are formed from epithelial strands. At the 8th week of embryonic development, valfa cells are chemically determined by glucagon, and by the 12th week, insulin is detected in beta cells. The activity of both types of pancreatic islet cells increases between the 18th and 20th weeks of gestation.

After the birth of a child, the growth and development of the gastrointestinal tract continues. In children under 4 years of age, the ascending colon is longer than the descending colon.

Tubular (hollow) organs as part of their wall have three membranes: mucous, muscular and adventitious (or serous).

mucous membrane, tunicamucosa, lines the inner surface of the digestive, respiratory and genitourinary systems. The mucous membrane of various hollow organs has a fundamentally similar structure. It consists of the epithelial lining, lamina propria, muscular lamina, and submucosa. The epithelial lining is organ-specific and is called the "mucosal epithelium", epithelium mucosae . It can be multi-layered, as in the oral cavity, or single-layered, as in the stomach or intestines. Due to the small thickness and transparency of the epithelial lining, upon examination, the mucous membrane has a certain color (from faint pink to bright red). The color depends on the depth and number of blood vessels in the underlying layer - the lamina propria. There are no vessels in the epithelium itself.

lamina propria, lamina propria mucosae , located under the epithelium and protrudes into the last protrusions of microscopic size, which are called papillae, papillae. In the loose connective tissue of this plate, blood and lymphatic vessels, nerves branch, glands and lymphoid tissue are located.

The mucosal glands are a complex of epithelial cells embedded in the underlying tissue.

It should be noted that they penetrate not only into the lamina propria of the mucous membrane, but even into the submucosa. Glandular cells secrete (secrete) mucus or a secret necessary for the chemical processing of food. Glands can be unicellular or multicellular. The former include, for example, goblet cells of the colon mucosa, which secrete mucus. Multicellular formations secrete a special secret (saliva, gastric, intestinal juices). Deep penetration of the terminal sections of the glands into the mucous membrane contributes to their abundant blood supply. The multicellular glands of the mucosa differ in shape. There are tubular (in the form of a tube), alveolar (in the form of a bubble) and alveolar-tubular (mixed) glands.

The lymphoid tissue in the lamina propria consists of reticular tissue rich in lymphocytes. It occurs along the intestinal tube in a diffuse form or in the form of lymphoid nodules. The latter can be represented by single follicles, follicles lymphatici solitary, or large accumulations of lymphoid tissue, follicles lymphatici aggregati. The diameter of single follicles reaches 0.5-3, and the diameter of accumulations of lymphoid tissue is 10-15 mm.

muscularis mucosa,lamina muscularis mucosae, relies on the border with the submucosa and consists of 1-3 layers of smooth muscle cells. In the mucous membrane of the tongue, palate, gums, tonsils, such smooth muscle cells are absent.

submucosal base,body submucosa, lies on the border of the mucous and muscular membranes. In most organs, it is well expressed, and rarely the mucous membrane is located directly on the muscular membrane, i.e., the mucous base is poorly expressed. The submucosa plays important role wall structures of hollow organs. It provides a strong fixation of the mucous membrane. In its structure, the submucosal base is a loose connective tissue in which the submucosal vascular (arterial, venous and lymphatic) and submucosal nerve plexuses are located. Consequently, the submucosa contains the main intraorganic vessels and nerves. Loose connective tissue has high mechanical strength. It should be noted that the submucosa is firmly connected with the proper and muscular plates of the mucous membrane and loosely with the muscular membrane. Due to this, the mucous membrane is able to shift in relation to the muscular membrane.

The role of the mucous membrane is multifaceted. First of all, the epithelial lining and the mucus secreted by the glands provide mechanical and chemical protection of organs from damaging effects. The contraction of the mucous membrane itself and the secreted mucus facilitate the transport of the contents of the hollow organs. Accumulations of lymphoid tissue in the form of follicles or more complex tonsils play an important role in the biological defense of the body. The secrets of the glands of the mucous membrane (mucus, enzymes, digestive juices) are essential as catalysts or components of the main metabolic processes in the body. Finally, the mucous membrane of a number of organs of the digestive system carries out the absorption of nutrients and liquids. In these organs, the surface of the mucous membrane increases significantly due to folds and microvilli.

muscle sheath, tunicamuscularis, - this is the middle shell in the wall of a hollow organ. In most cases, it is represented by two layers of smooth muscle tissue with different orientations. circle layer, statumr circulare, located inside, directly behind the submucosa. longitudinal layer, stratum longitudinal, is external. The muscular membrane is also characterized by an organ-specific structure. It concerns especially the structure of muscle fibers, the number of their layers, location and severity. Muscle fibers in the wall of a hollow organ are often smooth in structure, but can also be striated. The number of layers of muscle fibers in some organs decreases to one or increases to three. In the latter case, in addition to the longitudinal and circular layers, an oblique layer of muscle fibers is formed. In some places, the smooth muscle fibers of the circular layer are concentrated and form sphincters (switching devices). Sphincters regulate the movement of contents from one organ to another. Examples include the common bile duct sphincter, the pyloric (pyloric) sphincter, the internal anal sphincter, the internal urethral sphincter, etc. Smooth muscle, which forms the muscular membrane of hollow organs, from a functional point of view, differs from striated muscle tissue. It has automatism, it contracts involuntarily and slowly. Smooth muscle fibers are abundantly supplied with blood and innervated. Between the circular and longitudinal layers in the composition of the muscular membrane are intermuscular vascular (arterial, venous and lymphatic) and nerve plexuses. Each layer contains its own vessels, nerves and nerve endings. It should be noted that in primary departments the digestive and respiratory systems, as well as in the final sections of the digestive and genitourinary systems, smooth muscle tissue is replaced by striated tissue. The latter allows you to perform controlled (arbitrary) actions.

The functional purpose of the muscular membrane as part of the wall of a hollow organ is as follows: providing the tone of the organ wall (tension), the possibility of moving and mixing the contents, contraction or relaxation of the sphincters.

Adventitial or serous membrane. The outer shell as part of the wall of hollow organs is represented by an adventitial, or serous, membrane. adventitia, tunica adventitia, available in those organs that are fused with surrounding tissues. For example, the pharynx, esophagus, duodenum, trachea, bronchi, ureter, etc. These organs cannot move, since their walls are fixed to the surrounding tissues. The adventitial sheath is built of fibrous connective tissue, in which vessels and nerves are distributed. Hollow organs with mobility, capable of changing their position in the human body and volume, have as an outer shell serous membrane, tunica serosa.

The serous membrane is a thin, transparent plate, the basis of which is also fibrous connective tissue, covered on the outside with one layer of flat cells - mesothelium. With the help of the subserosal layer, body subserosa, which is a loose connective tissue, the serous membrane is connected to the muscular membrane. In the subserous layer are the vascular and nervous subserous plexuses. The free surface of the serous membrane in the normal state is smooth, shiny, moistened with serous fluid. Serous fluid is formed by extravasation from the capillaries of the subserous vascular plexus. The stomach is covered with a serous membrane, small intestine, large intestine, part Bladder etc. The serous membrane as part of the wall of a hollow organ performs a delimiting (prevents the fusion of organs with each other in close contact), mobile (provides a change in the lumen and sliding) and plastic (performs a regenerative role in case of damage) functions.

Hollow organs contain a cavity surrounded by membranes. They usually contain at least 3-4 shells. Among them, the inner shell provides interaction with the external and internal environments (for example, the digestive tract organs) or with internal environments(blood vessels). Outside of the inner membrane in the alimentary canal, a submucosal layer containing the vascular and nerve plexus. It also provides mechanical mobility of the inner shell in relation to the outer shells. The outer shell separates the organ from the surrounding structures, separates it. between internal and outer shells there is a muscular membrane (organs of the gastrointestinal tract, arteries, uterus, oviduct, bronchi, etc.)

The serous membrane is a thin dense connective tissue membrane lining the inner surface of the body cavities of humans and animals. The serous membranes include the peritoneum, pleura, pericardium, etc.

Structure:

1) Mesothelium

2) Basement membrane

3) Superficial fibrous collagen layer

4) Surface diffuse elastic network

5) Deep longitudinal elastic mesh

6) Deep collagen layer

The serous membrane produces and absorbs specific serous fluid, which supports the dynamic qualities of the internal organs, performs protective, transudative, resorption, plastic, fixation functions. It develops from the splanchnotome, the serous cavity from the coelom.

Pelvic region sigmoid colon and the beginning of the straight line are covered with peritoneum from all sides (located intraperitoneally). The middle section of the rectum is covered with peritoneum only from the anterior and lateral surfaces (mesoperitoneally), and the lower one is not covered by it (extraperitoneally).

Structural components of the digestive tube develop in embryogenesis from various rudiments. The mucosal epithelium develops from the ectoderm. oral cavity, salivary glands and caudal rectum. Endoderm forms the epithelium of the middle section digestive tract, as well as small and large digestive glands. From the visceral sheet of the splanchnotome, the mesothelium of the serous membrane of the intestine is formed. Connective tissue elements, vessels, smooth muscle tissue of the digestive tube are laid from the mesenchyme. The glands of the oral cavity develop from the ectodermal epithelium, while those of the abdominal cavity develop from the endoderm.

The endodermal primary gut is divided into three sections:

1) anterior (anterior intestine), from which the posterior part of the oral cavity develops, the pharynx (with the exception of the upper area near the choanae), the esophagus, stomach, duodenal ampulla (including the place where the liver and pancreas ducts flow into it, as well as these organs) ;

2) middle department(middle intestine) that develops into the small intestine

3) back department (hindgut) from which the large intestine develops.

Respectively different function 3 shells of the primary intestine - mucous, muscular and connective tissue - acquire in different departments digestive tube different structure.

Anomalies: oral cavity - cleft lip, cleft palate, macrostomy; pharynx - fistulas; small intestine - Meckel's diverticulum, large intestine - atresia, organ inversion

The oral cavity is divided into two sections: the vestibule of the mouth and the oral cavity itself. Through the mouth opening, the vestibule of the mouth opens outward.

The boundaries (walls) of the vestibule of the oral cavity in front are the lips, from the sides outside - the cheeks, from the inside - the labio-buccal surfaces of the teeth and alveolar processes jaws.

In the vestibule of the oral cavity, the ducts of the parotid salivary glands open. Under the mucous membrane in the center mandible there is a chin hole.

The oral cavity extends from the teeth in front and laterally to the entrance to the pharynx from behind. Top wall the oral cavity is formed hard sky. At the anterior end of the longitudinal palatine suture there is an incisive opening leading to the canal of the same name. In the posterolateral corners of the palate, the large and small palatine openings, the pterygopalatine canal, are symmetrically located. Back wall The oral cavity is represented by the soft palate. The lower wall is formed by the diaphragm of the mouth and is occupied by the tongue.

A child is born without teeth and with some underdevelopment of the lower jaw.

Innervation of the mucous membrane of the hard and soft palate carried out by 2 branches trigeminal nerve through the pterygopalatine ganglion, from which the palatine nerves depart. The muscles of the soft palate are innervated by the 3rd branch of the trigeminal nerve and the branches of the pharyngeal plexus.

Blood supply: infraorbital and inferior alveolar arteries (veins)

The tongue represents a muscular organ. Language has a body and a root. Its convex upper surface is called the back. From the sides, the tongue is limited by edges. In the back of the tongue, two sections are distinguished: the anterior, larger (about 2/s); the posterior section faces the pharynx.

Tongue papillae:

filiform and conical papillae.

2. mushroom-shaped papillae (at the top and along the edges of the tongue)

3.gutter-like papillae (located anterior to the dividing sulcus).

4. foliate papillae, located along the edges of the tongue.