One of the most important sections of anatomy for understanding the structure of the human body is the study of the hormonal system. In order to understand this complex and multilevel structure, it is better to refer to a schematic table of the endocrine glands, their hormones and functions. With its help, you can understand this issue in more detail.
What are glands in general and what are endocrine glands?
Iron is an organ in the human or animal body that produces and releases certain biologically active substances necessary to maintain life. These substances are called secrets. They can be released into the internal channels of the human body - into the blood, lymph - or out. According to this criterion, the glands are divided into organs of internal, external and mixed secretion. Endocrine glands are organs of internal secretion: they do not have output ducts. In general, they make up the endocrine system. Table"Glands and Hormones" shows this more clearly.
Endocrine system
It is a functional interconnection of tissues, cells and endocrine glands that secrete secret (hormones) into the bloodstream, lymph flow and intercellular fluid and thus carry out hormonal regulation. It traditionally has three sections:
- An endocrine gland system that has no additional tasks. The result of its production are hormones.
- The system of glands of mixed secretion, which, in addition to endocrine, also performs other functions. It includes the thymus, pancreas and gonads.
- The system of glandular cells that secrete hormone-like substances. The hormones produced by these organs enter directly into the circulatory system, lymph or tissue fluid.
Functions of the endocrine glands and their hormones
The table below describes the multiple tasks of this system. The main thing is that it produces hormones that control and are responsible for the normal course of the vital processes of the body. Thus, firstly, the endocrine system performs the function of chemical regulation, coordinates the work of all organs, is responsible for the processes of hematopoiesis, metabolism, etc. Secondly, it maintains the balance of the internal environment of the body, helps it adapt to the effects of the external environment. Thirdly, along with other systems, it participates in the regulation of the growth and development of the organism, its sexual identification and reproduction, as well as in energy-forming and energy-saving processes. The mental activity of the body is also very dependent on the endocrine system of glands and hormones (functions in the table).
Pituitary
This is a gland of very small size, but of great importance for the normal functioning of all organs. The pituitary gland is located in the fossa of the sphenoid bone of the skull, is associated with the hypothalamus and is divided into three lobes: anterior (adenohypophysis), intermediate and posterior (neurohypophysis). All the main hormones are produced in the adenohypophysis: somatotropic, thyrotropic, adrenocorticotropic, lactotropic, luteinizing, follicle-stimulating - they control the excretory activity of the peripheral endocrine glands. The role of the neurohypophysis, that is, the posterior lobe, is that hormones produced by the hypothalamus move into it along the pituitary stalk: vasopressin, which is involved in regulating the water content in the body, increasing the degree of reabsorption of fluid in the kidneys, and oxytocin, with the help of which smooth muscle contraction.
Thyroid
The thyroid gland is a very important endocrine gland that produces iodine-containing hormones. The function of the hormones (table below) of this gland is to promote metabolism, cell growth and the whole organism as a whole. Its main hormones are thyroxine and triiodothyronine. There is also a third hormone secreted by the thyroid gland - calcitonin, which is responsible for the concentration of calcium and phosphate in the body and prevents the formation of cells that destroy bone tissue. It also activates the reproduction of youngbone tissue cells. They are involved in the regulation of mitochondrial activity, where oxidation processes take place with the release of energy-saturated molecules. Due to insufficient production of these hormones, energy metabolism suffers: the heart begins to contract less frequently and weaker, resulting in swelling. Lack of iodine causes thickening of the thyroid tissue, resulting in a goiter. In order to prevent thyroid diseases, potassium iodide is often included in table s alt. With excessive work of this organ, excess energy is produced: the activity of the heart increases, pressure rises, oxidative reactions accelerate, a person loses weight. This can lead to serious illness.
Parathyroid glands
The anatomy of the endocrine glands and their hormones (table below) also includes four parathyroid glands, they are oval in shape and located in the tissues between the thyroid gland and the esophagus. The main hormone they produce is parathyrin (parathormone). Its main function is to regulate the level of ions in the blood. If it rises, the calcium level also increases, while the phosphate content remains unchanged. Excessive secretion of parathyroid hormone can provoke degradation and demineralization of bone tissue, which is fraught with bone fractures and muscle weakness. Insufficient release of this hormone causes a sharp increase in muscle and nervous excitability, up to the development of convulsive attacks.
Pancreas
This large secretory organ is located betweenduodenum and spleen. The intrasecretory part of the pancreas is called the islets of Langerhans. They are cells of various types that produce polypeptide hormones: glucagon, which stimulates the breakdown of glycogen carbohydrate in the liver, thereby increasing blood glucose and maintaining it at a constant level. Insulin, which regulates the metabolism of proteins, fats and carbohydrates, lowers blood glucose levels. Somatostatin, which inhibits the synthesis of growth hormone, insulin and glucagon, is a pancreatic polypeptide that stimulates the production of gastric juice and inhibits pancreatic secretion. Ghrelin, which increases appetite. Impaired secretion of glucagon and insulin can lead to diabetes.
Adrenals
These are small, pyramid-shaped glands located on top of the kidneys. The table of hormones of the endocrine glands indicates that this organ produces hormones in its two sections - the brain and the cortex. In the cortical region, which is divided into three zones, corticosteroids are produced. In the first zone (glomerular), mineralocorticoid hormones are produced that control mineral and ion exchange in cells and maintain their electrolyte balance. In the second, beam zone, there are glucocorticoids that monitor the metabolism of proteins, fats and carbohydrates, and in the third, reticular zone, sex hormones (androgens).
The adrenal medulla transports catecholamines into the blood: norepinephrine and adrenaline. Norepinephrine controls the nervous processes in the sympathetic zone. Catecholamines are involved inregulation of fat and carbohydrate metabolism, promote adaptation to stress, releasing adrenaline in response to emotional stimuli.
Thymus gland
The thymus, or thymus, is a small organ located behind the sternum, above the collarbone. It governs the functioning of the immune system throughout human life. However, the thymus gland decreases and becomes weaker with age - from childhood to puberty, its function is as active as possible, and then it gradually decreases. This gland produces several hormones: thymalin, thymosin, insulin-like growth factor, thymic humoral factor. The thymus is responsible for immunity, is involved in the regulation of energy metabolism and lymph flow, and also produces and activates T-lymphocytes necessary to provide antitumor and antiviral protection. If the functionality of the thymus is reduced, immunity is also reduced.
Pineal Gland
The pineal gland (pineal gland) is located in the middle of the brain, between the hemispheres, next to the hypothalamus. Its main function is the regulation of daily human biorhythms. The pineal gland secretes the hormones melatonin and serotonin. Melatonin has a calming, relaxing effect, prepares the body for sleep. In addition, it reduces stress and strengthens the immune system. Serotonin is the raw material for the production of melatonin. During the day, it enters the bloodstream and acts in the same way as serotonin, which is produced by other cells.
Sex glands
The gonads include: in men - the testes, in women - the ovaries. The testicles produce spermatozoa, but they also secrete male hormones - androgens, such as testosterone, which is responsible for the manifestation of secondary sexual characteristics, into the internal environment of the body. The ovaries in women produce eggs, which are absorbed into the external environment, and female hormones - estrogens, which enter inside. Thanks to these hormones, secondary female sexual characteristics appear, and they also have a direct impact on the quality of the ovaries. At the same time, both male and female sex glands produce both androgens and estrogens. During normal development in the body of any man there is a small amount of female hormones, and in the female body - a little male. The following table shows the physiology of the endocrine glands and their hormones more clearly.
| Iron and its hormones | Effect on the body | Hyperfunction | Hypofunction |
|
Pituitary gland (anterior lobe): thyrotropin |
Regulates the secretion of thyroid hormones | Graves' disease | Glandular atrophy |
| Corticotropin | Controls the synthesis and secretion of hormones of the adrenal cortex, affects the synthesis of glucocorticoids | Possible Itsenko-Cushing's disease | Decreased activity of the adrenal cortex |
| Somatropin | Growth hormone, ensures the development of the body | At a young age - gigantism, in adults - acromegaly | |
| Prolactin | Promotes milk production | Isolation of colostrum, irregular menstruation | Cessation of lactation |
| Follitropin | Stimulates the production of germ cells | Uterine bleeding | Lack of ovulation and infertility in women, in men - impotence, testicular atrophy |
|
Pituitary gland (posterior lobe): vasopressin |
Stimulates water reabsorption by the kidneys | Risk of water intoxication | Manifested as diabetes insipidus |
| Oxytocin | Stimulates smooth muscle contractions | Hypertension | Diabetes Insipidus |
|
Thyroid: Thyroxine, triiodothyronine |
Controls metabolism, increases the excitability of the nervous system | Graves' disease (metabolism increases, goiter develops) | Myxedema (metabolism decreases, puffiness appears) |
|
Parathyroid: parathyrin |
Regulationblood ion levels | Bone pain, skeletal deformity, possible nephrocalcinosis | Neuromuscular excitability increases, convulsions, lethargy, body temperature drops. |
|
Adrenal gland (cortex): aldosterone |
Normalizes the metabolism of minerals and organic substances, the production of sex hormones | Hypertension at a young age | Addison's disease. Acute or chronic adrenal insufficiency |
| Glucocorticoids (cortisol, corticosterone) | Anti-stress and immunoregulatory action, influence on metabolism. | Hypercortisolism, excess cortisol weakness, excess body weight, high blood pressure, skin problems | Addison's disease |
|
Adrenal gland (medulla): catecholamines (adrenaline, norepinephrine) |
Stress adaptation responses, fatty acid production, glucose mobilization, energy maintenance | Adrenal medulla tumor | |
|
Pancreas: insulin |
Normalizes blood glucose levels, synthesizes glycogen | Shock, fainting | Diabetes mellitus, increases blood glucose, sugar in urine |
| Glucagon | The opposite of insulin | ||
|
Gens: androgens |
Influence the development of sexual characteristics, the activity of the reproductive system and metabolic processes | Seborrhea, acne. In women - increased hair growth on the arms, legs, face, risk of miscarriage, infertility | Slows down puberty and development of genital organs, breast growth, loss of strength, infertility |
| Estrogens, progesterone | The quality of the female and male genital organs | Prostate atrophy, obesity | Osteoporosis |
|
Pineal gland (pineal gland): melatonin |
Regulates the body's circadian rhythms | Aging of the body slows down | Sleep disorders, anxiety, depression, cardiovascular problems |
|
Thymus gland: thymosin |
Stimulates the production and maturation of lymphocytes | Hyperplasia of the lymphoid apparatus | Immunity decreases, the number of T-lymphocytes in the blood decreases |
As you can see from the table, the endocrine glands, their hormones and the functions of these hormones are quite diverse.
In order to understand how the human body functions and what you need to do to maintain your he alth, it is imperative to understand how the endocrine system works, which regularly supplies our body with the necessary substances.
