The adrenal glands are located at the upper ends. What hormones do the adrenal glands produce? Treatment of adrenal diseases

The human endocrine system has a complex structure; it is responsible for the regulation of hormonal levels and consists of several organs and glands, among which the thyroid gland, pancreas and adrenal glands occupy an important place. A lot is known about the first two glands, but not everyone has heard about such an organ as the adrenal glands. Although this organ takes an active part in the functioning of the whole organism, disturbances in its functioning can lead to serious and sometimes severe diseases. What are the adrenal glands, what functions do they perform in the human body, what are the symptoms of adrenal diseases and how to treat these pathologies? Let's try to figure it out!

Basic functions of the adrenal glands

The adrenal glands are a powerful reserve for our body. For example, if the adrenal glands are healthy and cope with their function, a person does not experience fatigue or weakness during stressful situations. When these organs do not function well, a person who has experienced stress cannot recover for a long time. Even after experiencing a shock, a person still feels weak, drowsy for another 2–3 days, has panic attacks, and nervousness. Such symptoms indicate possible disorders of the adrenal glands, which are not able to resist nervous disorders. During prolonged or frequent stressful situations, the adrenal glands increase in size, and during prolonged depression they cease to function correctly and produce the required amount of hormones and enzymes, which over time leads to the development of a number of diseases that significantly worsen a person’s quality of life and can lead to serious consequences. Each adrenal gland produces hormones and consists of an inner medulla and an outer cortex, which differ from each other in their structure, hormone secretion and origin. Hormones of the adrenal medulla in the human body synthesize catecholamines, which are involved in the regulation of the central nervous system, cerebral cortex, and hypothalamus. Catecholamines affect carbohydrate, fat, and electrolyte metabolism and are involved in the regulation of the cardiovascular and nervous systems. Cortical substance, or in other words, steroid hormones, are also produced by the adrenal glands. Such adrenal hormones are involved in protein metabolism, regulate water-salt balance, as well as some sex hormones. Disturbances in the production of adrenal hormones and their functions lead to disruption in the whole body and the development of a number of diseases.

Adrenal hormones

Norepinephrine is a stress hormone that is considered a precursor to adrenaline. It has less impact on the human body and is involved in the regulation of blood pressure, which allows stimulating the work of the heart muscle. The adrenal cortex produces hormones of the corticosteroid class, which are divided into three layers: glomerular, fascicular and zona reticularis. Hormones of the adrenal cortex of the zona glomerulosa produce:

• Aldosterone is responsible for the amount of K+ and Na+ ions in human blood. Participates in water-salt metabolism, increases blood circulation, increases blood pressure.
• Corticosterone is a low-active hormone that takes part in the regulation of water-salt balance.
• Deoxycorticosterone is a hormone produced by the adrenal glands, which increase resistance in our body, gives strength to muscles and skeleton, and also regulates water-salt balance.

• Cortisol is a hormone that preserves the body's energy resources and is involved in carbohydrate metabolism. The level of cortisol in the blood often fluctuates, so in the morning there is much more of it than in the evening.
• Corticosterone, the hormone described above, is also produced by the zona fasciculata of the adrenal glands.

• Androgens are sex hormones.

The first signs of adrenal disease

Androgen deficiency in boys, especially during intrauterine development, leads to the development of abnormalities of the genital organs and urethra. In medicine, this condition is called “pseudohermaphroditism.” In girls, a deficiency of this hormone leads to delayed puberty and absence of menstruation. The first signs and symptoms of adrenal diseases develop gradually and are characterized by:

• increased fatigue;
• muscle weakness;
• increased irritability;
• sleep disturbance;
• anorexia;
• nausea, vomiting;
• hypotension.

Diseases of the adrenal glands and their description

• frequent headaches;
• decreased visual acuity;
• decreased taste buds;
• excessive pigmentation of some areas of the body.

Treatment of adrenal insufficiency is carried out by the correct selection of medications that affect the hypothalamic-pituitary system. If conservative treatment is ineffective, patients are prescribed surgery. Addison's disease is a chronic adrenal insufficiency that develops with bilateral damage to the adrenal glands. During the development of this disease, the production of adrenal hormones decreases or completely stops. In medicine, this disease can be found under the term “bronze disease” or chronic adrenal insufficiency. Most often, Addison's disease develops when the adrenal tissue is damaged by more than 90%. The cause of the disease is often autoimmune disorders in the body. The main symptoms of the disease are:

• severe pain in the intestines, joints, muscles;
• disturbances in the functioning of the heart;
• diffuse changes in the skin and mucous membranes;
• decrease in body temperature, which gives way to severe fever.

Itsenko-Cushing syndrome is a condition in which there is an increased secretion of the hormone cortisol. The characteristic symptoms for this pathology are uneven obesity, which appears on the face, neck, chest, abdomen, and back. The patient's face becomes moon-shaped, red with a cyanotic tint. Patients experience muscle atrophy, decreased muscle tone and strength. With Itsenko-Cushing syndrome, typical symptoms are a decrease in muscle volume in the buttocks and thighs, and wasting of the abdominal muscles is also noted. The skin of patients with Itsenko-Cushing syndrome has a characteristic “marble” shade with noticeable vascular patterns, also peels, feels dry to the touch, rashes and spider veins are noted. In addition to skin changes, patients often develop osteoporosis, severe muscle pain, and joint deformation and fragility. From the cardiovascular system, cardiomyopathy, hypertension or hypotension develops, followed by the development of heart failure. In addition, with Itsenko-Cushing syndrome, the nervous system is severely affected. Patients with this diagnosis are often inhibited, prone to depression and panic attacks. They think about death or suicide all the time. In 20% of patients with this syndrome, steroid diabetes mellitus develops, in which there is no damage to the pancreas.

Tumors of the adrenal cortex (glucocorticosteroma, aldosterone, corticoestrom, andodosteroma) are benign or malignant diseases in which proliferation of adrenal cells occurs. An adrenal tumor can develop from both the cortex and medulla and have different structures and clinical manifestations. Most often, the symptoms of an adrenal tumor manifest themselves in the form of muscle tremors, increased blood pressure, tachycardia develops, increased agitation, a feeling of fear of death, pain in the abdomen and chest, and copious urine output. If treatment is not done in a timely manner, there is a risk of developing diabetes mellitus and impaired renal function. If the tumor is malignant, there is a possible risk of metastases to neighboring organs. Treatment of tumor-like processes of the adrenal glands is possible only by surgery.

Pheochromocytoma is a hormonal tumor of the adrenal glands that develops from chromaffin cells. Develops as a result of excess amounts of catecholamine. The main symptoms of this disease are:

• increased blood pressure;
• increased sweating;
• constant dizziness;
• severe headaches, chest pain;
• labored breathing.

Diagnosis of adrenal diseases

Treatment of adrenal diseases

Operations are performed endoscopically or abdominally. Abdominal surgery consists of a surgical intervention that requires a long period of rehabilitation. Endoscopic surgery is a more gentle procedure that allows patients to quickly recover after surgery. The prognosis after treatment for adrenal diseases is favorable in most cases. Only in rare cases, when the patient has a history of other diseases, complications may appear.

Pathologies of the adrenal glands are easier to treat in the initial stages of their development, so at the first symptoms or long-term ailments, you should not self-medicate or ignore the first signs. Only timely and high-quality treatment will bring success in treatment.

Most people do not know what the adrenal glands are, what they look like and what role they play in the body. The adrenal glands are endocrine glands that take an active part in the functioning of the body. Metabolic processes, control of hormonal levels, formation of protective forces - this is not the entire list of functions in which the organ participates.

The adrenal glands are an important human gland that performs a humoral function.

Where are they located?

Topography

The adrenal glands are classified as endocrine glands because they are paired glands and occupy a position in the superomedial surface at the superior points of the kidneys. The adrenal glands are located in the retroperitoneal space and are located on both sides of the spine, at the height of the 11-12th thoracic vertebra. The posterior border of the fascial capsule, which encloses both glands, is adjacent to the lumbar diaphragm.

Syntopy of glands

The adrenal glands consist of an external (outer), posterior, and renal surface. In relation to the internal organs, the paired glands occupy the following position:

• Right adrenal gland:
  • the bottom is adjacent to the upper corner of the kidney;
  • in front it borders with the extraperitoneal edge of the liver;
  • the central side faces the great vein;
  • the posterior edge borders the lumbar diaphragm.
• Left adrenal gland:
  • borders on the upper left corner of the kidney;
  • in front it comes into contact with the posterior wall of the omental foramen and the stomach;
  • located behind the diaphragm;
  • the pancreas and splenic vessels are formed below.

Embryology

The gland embryos develop in the fetus in the 1st month of intrauterine development, their length is about 5-6 mm. The embryo is formed as a proliferation of peritoneal tissue. The growth deepens into the connective tissue embryo and subsequently separates from the layer of flat cells. The embryo is an independent body that will form cortical matter. Elements of the solar plexus of the sympathetic nervous system form the adrenal medulla. Characteristic roughness appears by the end of the 4th month of embryonic development.

Anatomy of the adrenal glands

The adrenal glands are located inside the subcutaneous fatty tissue and the renal membrane. The body, lateral and medial legs are the structure of the gland. The right-located gland looks like a triangular pyramid, the left one looks like a lunar crescent. The front and back surfaces are covered with folds. The deepest one is located closer to the middle of the surface and is called the gate. In the left gland the gate is located near the base, and in the right - near the apex.

Characteristic dimensions

The color of the outer surface is yellow or brown. From the moment of birth and throughout the period of growing up, the mass and size of the adrenal glands change. The mass of the adrenal glands in a newborn is about 6 g, in an adult from 7 to 10 g. The length reaches approximately 6 cm, width 3 cm, thickness 1 cm. The left gland is slightly larger than the right.

Structure of the gland

The structure of the glands is similar to that of a fruit. Each gland consists of 3 layers, a brief description is described in the table:

The adrenal cortex and the medulla are independent glands that participate in the production of hormones.

Gland bark

Cartisol, androgens, aldosterone are hormones produced by the adrenal cortex. Cells of the cortical layer also participate in the process. In the absence of disorders of the adrenal cortex and external influences on it, the number of hormones produced is 35-40 mg. The cortex has 3 layers. This division can be seen at a level invisible to the naked eye. Each layer has different functions and produces different substances that affect the physiological processes of the body.

Zona glomerulosa

It consists of rectangular cells, which are united into small groups - glomeruli. They have formed a network of capillaries that penetrate the liquid cell layer. To regulate blood pressure, aldosterone, corticosterone, and deoxycorticosterone are needed. It is the zona glomerulosa that is the main site of their formation.

Beam zone

The widest zone of the glandular cortex is located between the glomerular and reticular layers. It is formed by long, light multifaceted cells located across the surface of the glands. Elements of the zona fasciculata are responsible for the secretion of corticosterone and cortisol. They are needed to regulate the processes of metabolism of fats, proteins and carbohydrates in the human body.

Mesh zone

Small, rectangular cells form small connections. This is the third inner layer, which is responsible for the synthesis of androgens. The main hormones that are produced in the reticular zone are:

• dehydroepiandrosterone;
• adrenosterone;
• estrogen;
• testosterone;
• pregnenolone;
• dehydroepiandrosterone sulfate;
• 17-hydroxyprogesterone.

Brain matter

The center of the glands is the medulla. It consists of large cells and is colored yellow-brown. Its cells are responsible for the synthesis of norepinephrine and adrenaline and the delivery of these substances into the blood. Such a hormone is needed to bring all systems and internal organs to full readiness in case of a threat. The process begins only after the sympathetic nervous system transmits an “instruction” through the spinal cord.

Blood supply and innervation

Features of the blood supply include a large supply of blood per 1 g. tissues compared to other organs.

Three large blood arteries out of 50 that provide joint blood supply to the adrenal glands and kidneys are:

• the superior main adrenal artery, which arises from the phrenic inferior blood vessel;
• middle artery (supplied by the abdominal blood vessel);
• inferior artery (connected to the renal artery).

Some vessels supply blood only to the cortex, others pass through it and nourish the medulla. Wide capillaries create a blood supply to the central blood vessel. The central vein from the left gland enters the renal artery, and from the right gland into the inferior vena cava. In addition, many small blood vessels leave the paired glands and flow into the branches of the portal vein.

A network of lymphatic capillaries connects to the lumbar nodes of the lymphatic system. The vagus nerves provide the paired glands with nerve elements. In addition, the set of nerve elements of the solar plexus provides the medulla with preganglionic sympathetic fibers. Innervation occurs thanks to the nerve elements of the abdominal, adrenal and renal plexuses.

The human body is designed in such a way that even any small organ bears a great responsibility for the coordinated functioning of the entire system. There is also a paired gland that is capable of producing several types of hormones, without which life is impossible. The adrenal glands, an organ belonging to the endocrine system, take an active part in metabolism. Once you understand what adrenal hormones are, you will be able to take better care of this little-known component of an essential system. Find out what groups hormones are divided into, their structure, normal indicators and causes of failure.

The structure of the adrenal glands and features of their work

Before talking about the hormones of an organ such as the adrenal glands, it is worth dwelling on its definition and structure. Despite their name, the adrenal glands are not an appendage of the kidneys, although they are located directly above them. The paired gland has a different structure for the right and left adrenal glands. Each of them in an adult weighs about 10 g and is up to 5 cm long, surrounded by a layer of fat.

The adrenal gland is surrounded above by a capsule. Lymphatic vessels and veins pass through a deep groove called the hilum. Nerves and arteries pass through the anterior and posterior walls. According to its structure, the adrenal gland is divided into the outer cortex, which occupies up to 80% of the main total volume, and the inner medulla. Both are responsible for the production of different hormones.

Brain matter

Located in the deeper part of the gland, the medulla consists of tissue containing a large number of blood vessels. Thanks to the medulla, in situations of pain, fear, and stress, two main hormones are produced: adrenaline and norepinephrine. The heart muscle begins to contract vigorously. Blood pressure rises and muscle spasms may occur.

Cortex

On the surface of the adrenal gland there is a cortex, the structure of which is divided into three zones. The zona glomerulosa, located under the capsule, contains a cluster of cells collected in irregularly shaped groups that are separated by blood vessels. The fascicular zone forms the next layer, consisting of strands and capillaries. Between the medulla and the cortex there is a third zone - the reticular one, which includes larger strands of dilated capillaries. Hormones of the adrenal cortex take part in the process of body growth and metabolic functions.

Groups of adrenal hormones and their effect on the body

Each group of hormones produced by the adrenal glands is important and necessary. Deviations from the norm, both in one direction and the other, can lead to diseases of the adrenal glands and malfunctions of the entire body. The relationship is disrupted, which negatively affects many organs in a chain reaction. It is worth dwelling on the names of the main three groups of adrenal hormones that are important for humans and their functions.

Mineralocorticoids: aldosterone

The synthesis processes occurring in the adrenal cortex produce a large number of different compounds. The hormone aldosterone is the only one that enters the blood among all mineralocorticoids. By influencing the water-salt balance of the body, aldosterone balances the ratio of external and internal amounts of water and sodium. Under its influence on vascular cells, water is transported inside the cells, thereby increasing blood circulation.

Glucocorticoids: cortisol and corticosterone

Cortisol and corticosterone are produced in the pars fasciculata of the cortex. Glucocorticoids are involved in all metabolic processes in the body and are responsible for the speed of metabolic processes occurring. Metabolic reactions lead to the breakdown of protein in tissues, through the circulatory system they enter the liver, then the metabolites turn into glucose, which is the main source of energy.

When the level of cortisol in the blood does not go beyond the permissible limit, it acts as a protective barrier for cells. Excess of the adrenal hormones cortisol and corticosterone can increase the production of gastric secretions and lead to ulcers. Fat deposits appear in the abdomen and waist, diabetes may develop, and the level of immunity will decrease.

Steroids: male and female sex hormones

Important hormones for the human body are sex hormones, which are responsible for timely maturation, a woman’s bearing a fetus during pregnancy, and procreation. In men, the hormone testosterone is produced in the testes. The female hormone estrogen and progesterone prepare a woman for the period of bearing a child. An increased level of steroids in the body sharply increases appetite, body weight begins to increase, and the following appear:

• obesity;
• arrhythmia syndrome;
• diabetes;
• swelling.

In women, when there is an excess of steroids that need to be reduced, there are menstrual irregularities, mood swings, and lumps often appear in the mammary glands. When the hormonal norm in women is disrupted, below the permissible value, the skin becomes dry, flabby, and the bones are weak and fragile. In a sports environment, the use of synthetic steroid hormones for the purpose of quickly increasing muscle mass is equated to doping.

Causes and signs of hormonal imbalance

Factors that can cause hormonal imbalance sometimes depend on lifestyle. But often a person suffers due to circumstances beyond his control, dictated by age or other conditions. The causes of hormonal imbalance can be:

• hereditary genetics;
• long-term use of medications, including contraceptives;
• puberty;
• pregnancy and childbirth in women;
• female menopause;
• frequent smoking;
• alcohol addiction;
• dysfunction of the thyroid gland, kidneys, liver;
• prolonged depression, stress;
• sudden weight changes.

Endocrine adrenal insufficiency has a number of symptoms. From them, the doctor can determine that certain functions in the body that are responsible for hormonal levels are disrupted. Signs indicating that adrenal pathology exists:

• unreasonable irritability, nervousness;
• acute periods of PMS in women;
• violation of the menstrual cycle in women;
• adenoma;
• sleep disturbance;
• increased fatigue;
• erectile dysfunction in men;
• female frigidity;
• infertility;
• hair loss;
• acne, skin inflammation;
• increased swelling;
• sudden weight fluctuations for no reason.

In what cases is analysis prescribed?

Hormonal tests are carried out only if the doctor suspects a particular disease associated with the endocrine system, if signs of infertility or inability to bear a child appear. Blood is donated for hormone testing to clarify or refute the diagnosis. If concerns are confirmed, treatment with tablets is prescribed. If in doubt, testing for adrenal hormones is repeated at intervals prescribed by the doctor.

Do you need preparation for the study?

To get a reliable test result for adrenal hormones, you need to fulfill a few simple conditions:

• take a blood test in the morning on an empty stomach;
• at least 6 hours must pass between it and the last meal;
• smoking cessation is required within 4 hours;
• avoid stressful situations the day before;
• Avoid physical activity several hours before donating blood;
• do not use contraceptives for two weeks;
• in case of impaired renal function, the daily amount of urine is collected;
• for women - know the day of the menstrual cycle.

Indicators of normal adrenal hormones

For different types of hormones, indicators may vary depending on age, time of day, and even what position the patient was in when taking the test: lying or sitting. How to check the adrenal glands after receiving the results of hormone tests? Compare your readings with the transcript issued by the laboratory. The main types of hormones and their average standards are indicated in the summary table:

Video about diseases associated with adrenal hormones

Small endocrine glands play a big role in the life of any person. You will learn about their meaning by watching the proposed video and photo. Glands with a lack or excess of production of substances provoke diseases. Adrenal hormones are responsible for many functions of the body - from maturation to the ability to procreate, feel healthy, beautiful, and happy. How to recognize the signs and symptoms of adrenal disease, disruption of their functioning, how to reduce high levels of the hormone, increase production, you will understand by watching the video.

Attention! The information presented in the article is for informational purposes only. The materials in the article do not encourage self-treatment. Only a qualified doctor can make a diagnosis and make recommendations for treatment based on the individual characteristics of a particular patient.

As is known, in the human body there are many mechanisms necessary for the regulation of life. One of them is the endocrine system, which is responsible for the formation and secretion of hormones. It includes organs such as the thyroid and pancreas, adrenal glands, and reproductive cells. Each of them is responsible for the secretion of certain hormones and their own functions. One of the most important endocrine glands is the adrenal glands. Despite their small size, they provide regulation of many processes occurring in the human body. This is due to the fact that the adrenal glands secrete several hormones at once, each of which performs a specific role.

Functions and structure of the adrenal glands

The adrenal glands are paired organs that are located in the retroperitoneum. They are located right on the upper surface of the kidneys and have their own capsule. The right and left glands differ from each other in shape, but have approximately the same size and location. Both adrenal glands consist of two layers: the cortex and the medulla. The first occupies the bulk of the thickness of the organs. Thanks to it, water-salt balance, mineral metabolism are maintained, and sexual functions are also ensured. The adrenal medulla occupies a smaller part, but its role is also very important for life. Thanks to it, hormones such as adrenaline and norepinephrine enter the blood. These substances are necessary not only for the normal functioning of the heart, but are also one of the main mediators of the nervous system. The structure and functions of the adrenal glands are directly related to each other, since each zone of these organs is responsible for the production of its own hormone. This allows you to diagnose disorders of a specific area of ​​the gland.

Adrenal cortex

Beneath the fibrous capsule is the adrenal cortex. It occupies 90% of the thickness of the gland. In turn, this layer is divided into 3 parts. The zona glomerulosa, zona fasciculata and reticularis are part of one anatomical formation called the “adrenal cortex.” The functions of each of these layers are different. They are associated with hormones that are produced in a particular zone. The glomerular layer is responsible for maintaining mineral metabolism in the body. It releases hormones such as aldosterone and corticosterone into the blood. Thanks to their action, the functioning of the renal tubules is regulated, as a result of which excess fluid is not retained in the body. In addition to maintaining ion exchange, these hormones help maintain normal blood pressure. The functions of the adrenal glands are also determined by the zona fasciculata of the cortex. It produces glucocorticosteroids - the main regulators of carbohydrate, protein and fat metabolism. In addition, these hormones are in close relationship with catecholamines and insulin. Corticosteroids affect many processes occurring in the body. Among them are the suppression of inflammatory reactions, dilation of the bronchi, decreased immune response, etc. The reticular zone of the cortex produces androgens - sex hormones responsible for the formation of secondary sexual characteristics.

Adrenal medulla

The functions of the adrenal glands largely depend on the medulla. This is where adrenaline is produced. This hormone is responsible for such important indicators as blood pressure and pulse. Adrenaline, otherwise known as epinephrine, is released into the blood under the influence of stressful situations. At rest, the hormone is released only in small quantities. The adrenal medulla produces and stores adrenaline. The functions of this hormone are also related to the transmission of nerve impulses. In this case, adrenaline acts as a mediator.

Adrenal glands: hormones and functions in the body

Although the adrenal cortex and medulla secrete different hormones, they are all interconnected. The functions of the adrenal glands are performed due to the close interaction of both layers. For example, adrenaline is released into the blood with the help of corticosteroids, which, as it were, “signal” the body about stress. In addition, hormones of the zona fasciculata are responsible for the regulation of all types of metabolism, which occurs due to their relationship with the secretions of the pancreas and thyroid glands. Their effect is aimed at helping such biogenic amines as thyroxine, glucagon and adrenaline. They also regulate the production of insulin by pancreatic cells. All this is carried out by the adrenal glands; their functions in the body are very important for life. If these glands are disrupted, the entire endocrine system can be affected.

Functions of the adrenal glands in women and men

In addition to the fact that the adrenal glands are involved in many vital processes, they are responsible for a person’s appearance, voice and sexual behavior. All this is provided by sex hormones - androgens, produced in the reticular zone of the cortex. It can be argued that the functions of the adrenal glands in women and men are identical. However, thanks to androgens in the zona reticularis, secondary sexual characteristics appear during adolescence. In women, it is characterized by a lack of facial hair, a thin voice and breast growth. Androgens in men contribute to the development of muscle mass, the appearance of a mustache and beard, and behavioral changes during adolescence.

Adrenal gland dysfunction

Dysfunction of the adrenal glands leads to various consequences for the body. Manifestations depend on the spread of the lesion to the gland tissue. In addition, the disorder may be associated with both hyper- and hyposecretion of hormones. Depending on this, one or another function of the human adrenal glands suffers. The most common symptoms are: increased blood pressure, female obesity, increased skin pigmentation (most often on the abdomen), alopecia. In addition to these manifestations, there are more serious problems, such as combined disorders of all types of metabolism, hermaphroditism, hypertensive crisis with the development of heart attack and stroke.

Diseases caused by disorders of the adrenal cortex

There are many pathologies associated with disorders in the adrenal cortex. The most common of them are Cushing's disease and Conn's syndrome. The first is associated with increased formation and release of corticosteroids. The main manifestations of Itsenko-Cushing's disease: hyperglycemia, obesity of the face and upper half of the body, muscle weakness, increased pigmentation of the abdominal skin in the form of stripes (striae). Conn's syndrome develops when there is a disorder in the zona glomerulosa cortex. It is characterized by increased levels of aldosterone. Clinically, this is manifested by muscle weakness and cramps, itching, symptoms of diabetes - thirst and polyuria. Violations in the reticular zone in boys can lead to acceleration - early puberty or, on the contrary, to infantilism. Girls experience symptoms such as hirsutism - male-type hair growth, rough timbre of voice, underdevelopment of the mammary glands. In rare cases, disruption of the reticular zone leads to hermaphroditism. The combined deficiency of all cortical hormones is called Addison's disease.

Adrenal medulla disorder

Another function of the adrenal glands in the human body is related to the medulla. If this layer is disrupted, a disease such as pheochromocytoma develops. It is characterized by increased production and secretion of adrenaline into the blood. The consequences of this are an increase in blood pressure to critical values. The disease is often confused with hypertension and kidney disease. Its difference is that the increase in blood pressure occurs suddenly and reaches high numbers. In addition, the patient’s condition returns to normal just as unexpectedly. Hypertension with pheochromocytoma requires special treatment. The consequences of this condition are dangerous due to the development of a heart attack and acute cerebrovascular accident.

Diagnosis and treatment of adrenal diseases

Adrenal disease can be suspected based on clinical manifestations. The final diagnosis will become clear only after donating blood for hormone levels and instrumental examination methods (ultrasound, MRI, scintigraphy). The most common cause of disease is adrenal tumors. Pathologies associated with hypersecretion of hormones require surgical treatment. After surgery, adrenal function can be fully restored. Hormone deficiency requires lifelong replacement therapy.

The adrenal glands are located at the level of the XI-XII thoracic vertebrae. The right adrenal gland, like the kidney, lies slightly lower than the left. With its posterior surface it is adjacent to the lumbar part of the diaphragm, its anterior surface is in contact with the visceral surface of the liver and duodenum, and the lower concave (renal) surface is in contact with the upper end of the right kidney. The medial edge (margo medialis) of the right adrenal gland borders the inferior vena cava. The left adrenal gland is in contact with the aorta with its medial edge, and its anterior surface is adjacent to the tail of the pancreas and the cardiac part of the stomach. The posterior surface of the left adrenal gland is in contact with the diaphragm, the lower - with the upper end of the left kidney and its medial edge. Each adrenal gland (both right and left) lies in the thickness of the perirenal fat body. The anterior surfaces of the left and right adrenal glands are partially covered by the renal fascia and parietal peritoneum.

The mass of one adrenal gland in an adult is about 12-13 g. The length of the adrenal gland is 40-60 mm, height (width) - 20-30 mm, thickness (antero-posterior size) - 2-8 mm. The mass and size of the right adrenal gland are somewhat smaller than the left.

Sometimes additional ectopic tissue of the adrenal cortex is found in the body (in the kidneys, spleen, retroperitoneal area below the kidneys, along the aorta, in the pelvis, spermatic cord, broad ligament of the uterus). Possible congenital absence of one of the adrenal glands. A characteristic feature of their cortex is its ability to regenerate.

The structure of the adrenal glands

The surface of the adrenal gland is slightly lumpy. On the anterior surface, especially of the left adrenal gland, a deep groove is visible - the gate (hilum), through which the central vein exits the organ. On the outside, the adrenal gland is covered with a fibrous capsule, tightly fused with the parenchyma and extending into the depths of the organ numerous connective tissue trabeculae. Adjacent to the fibrous capsule from the inside is the cortical substance (bark; cortex), which has a rather complex histological structure and consists of three zones. Outside, closer to the capsule, is the glomerular zone (zona glomerulosa), behind it is the middle fasciculate zone (zona fasciculate), and on the border with the medulla is the internal reticular zone (zona reticularis). The morphological feature of the zones is the distribution of glandular cells, connective tissue and blood vessels that is unique to each zone.

The cortex accounts for about 90% of the adrenal tissue in an adult. This layer consists of three zones: the outer - glomerular, the middle - fasciculata and the inner (surrounding the medulla) - reticularis. Located directly under the fibrous capsule, the zona glomerulosa occupies approximately 15% of the volume of the cortex; its cells contain a relatively small amount of cytoplasm and lipids and produce the hormone aldosterone. The zona fasciculata accounts for 75% of the total cortex; its cells are rich in cholesterol and cholesterol esters and produce mainly cortisol (hydrocortisone). Cells of the zona reticularis also produce this substance; they are relatively poor in lipids and contain many granules. In addition to cortisol, the cells of this zone (like the fasciculata) produce sex hormones - androgens and estrogens.

The adrenal cortex produces more than 50 different steroid compounds. It serves as the only source of gluco- and mineralocorticoids in the body, the most important source of androgens in women, and plays a minor role in the production of estrogens and progestins. Glucocorticoids, named for their ability to regulate carbohydrate metabolism, are important for maintaining many vital functions and especially for ensuring the body's responses to stress. They also take part in the regulation of growth and development processes. The main glucocorticoid in humans is cortisol, and an excess or deficiency of this steroid is accompanied by life-threatening changes. Of the mineralocorticoids (so named for their ability to regulate salt metabolism), the main one in humans is aldosterone. An excess of mineralocorticoids causes arterial hypertension and hypokalemia, and a deficiency causes hyperkalemia, which may be incompatible with life.

Zona glomerulosa formed by small, prismatic cells arranged in small groups - glomeruli. In these cells, the endoplasmic reticulum is well developed; lipid droplets measuring about 0.5 μm are present in the cytoplasm. The glomeruli are surrounded by convoluted capillaries with fenestrated endothelium.

Beam zone (the widest part of the adrenal cortex) consists of large light multifaceted cells. These cells form long cords (bundles) oriented perpendicular to the surface of the adrenal gland. The cells of this zone have a well-developed non-granular endoplasmic reticulum, mitochondria, numerous lipid droplets, ribosomes, particles of glycogen, cholesterol and ascorbic acid. Between the strands of endocrinocytes there are blood capillaries with fenestrated endothelium.

Mesh zone are made up of small polyhedral and cubic cells that form small cellular clusters. Cells of the reticular zone are rich in elements of the non-granular endoplasmic reticulum and ribosomes.

The listed zones are functionally separate. The cells of each zone produce hormones that differ from each other not only in chemical composition, but also in physiological action. Hormones of the adrenal cortex are collectively called corticosteroids and can be divided into three groups: mineralocorticoids - aldosterone, secreted by cells of the zona glomerulosa; glucocorticoids: hydrocortisone, corticosterone, 11-dehydro- and 11-deoxycorticosterone, formed in the zona fasciculata; sex hormones - androgens, similar in structure and function to the male sex hormone, estrogen and progesterone, produced by the cells of the retinal zone.

Aldosterone is involved in the regulation of electrolyte and water metabolism, changes the permeability of cell membranes to calcium and sodium, and stimulates the formation of collagen. Glucocorticoids affect protein metabolism, increase the content of glucose in the blood, glycogen in the liver, skeletal muscles, and myocardium. Glucocorticoids also accelerate filtration in the glomeruli of the kidney, reduce the reabsorption of water in the distal convoluted tubules of the nephrons, and inhibit the formation of the main substance of connective tissue and the proliferation of fibroblasts.

In the center of the adrenal gland is the medulla, formed by large cells that are stained yellowish-brown with chromium salts. There are two types of these cells: epinephrocytes make up the bulk of cells and produce adrenaline, norepinephrocytes, scattered in the medulla in small groups, produce norepinephrine.

Adrenaline breaks down glycogen, reduces its reserves in the muscles and liver, increases the content of carbohydrates in the blood, being, as it were, an insulin antagonist, strengthens and accelerates the contraction of the heart muscle, narrows the lumen of blood vessels, thereby increasing blood pressure. The effect of norepinephrine on the body is similar to that of adrenaline, but the effect of these hormones on some functions can be completely opposite. Norepinephrine, in particular, slows the heart rate.

Adrenal development

The adrenal cortex and medulla are of different origins. The cortex differentiates from the mesoderm (from the coelomic epithelium) between the root of the dorsal mesentery of the primitive intestine and the urogenital fold. The tissue developing from mesodermal cells and located between the two primary buds is called interrenal tissue. It gives rise to the adrenal cortex, from which accessory adrenal glands (interrenal bodies, glandulae suprarenales accessoriae) are formed.

The adrenal medulla develops from embryonic nerve cells - sympathoblasts, which are evicted from the anlage of the nodes of the sympathetic trunk and turn into chromaffinoblasts, and the latter into chromaffin cells of the medulla. Chromaffinoblasts also serve as material for the formation of paraganglia, which in the form of small clusters of chromaffin cells are located near the abdominal aorta - aortic paraganglia (paraganglion aorticum), as well as in the thickness of the nodes of the sympathetic trunk - sympathetic paraganglia (paraganglia sympathica).

The introduction of future medulla cells into the interrenal adrenal gland begins in the 16 mm long embryo. Simultaneously with the unification of the interrenal and adrenal parts, differentiation of the cortical zones and maturation of the medulla occur.

Vessels and nerves of the adrenal glands

Each adrenal gland receives 25-30 arteries. The largest of them are the superior adrenal arteries (from the inferior phrenic artery), middle adrenal (from the abdominal aorta) and inferior adrenal arteries (from the renal artery). Some of the branches of these arteries supply blood only to the cortex, others pierce the adrenal cortex and branch in the medulla. From the sinusoidal blood capillaries, tributaries of the central vein are formed, which flows into the inferior vena cava at the right adrenal gland, and into the left renal vein at the left adrenal gland. Numerous small veins emerge from the adrenal glands (especially the left one), flowing into tributaries of the portal vein.

The lymphatic vessels of the adrenal glands drain into the lumbar lymph nodes. The innervation of the adrenal glands involves the vagus nerves, as well as nerves originating from the celiac plexus, which contain preganglionic sympathetic fibers for the medulla.

Age-related features of the adrenal glands

In a 5-6 week fetus, the primitive adrenal cortex forms in the retroperitoneal mesenchyme. Soon it is surrounded by a thin layer of more compact cells. In a newborn, the adrenal cortex consists of two zones - fetal and definitive. The former produces mainly the precursors of androgens and estrogens, while the function of the latter is probably similar to that of an adult. The fetal zone accounts for the bulk of the gland of the fetus and newborn. By the 2nd week of postnatal life, its weight decreases by a third due to degeneration of the fetal zone. This process begins in the prenatal period. The fetal zone completely disappears by the end of the first year of life. The final formation of the three zones of the adrenal cortex is delayed until 3 years of age. The adrenal glands then continue to enlarge (especially before and during puberty) and by the end of puberty they reach the size characteristic of an adult.