Regulation of Body Processes | Biology for Majors II

Describe how hormones regulate body processes

Hormones have a wide range of effects and modulate many different body processes. The key regulatory processes that will be examined here are those affecting the excretory system, the reproductive system, metabolism, blood calcium concentrations, growth, and the stress response.

Learning Objectives

• Explain how hormones regulate the excretory system
• Discuss the role of hormones in the reproductive system
• Describe how hormones regulate metabolism
• Explain the role of hormones in blood calcium levels
• Explain the role of hormones in growth
• Explain the role of hormones in stress

Hormonal Regulation of the Excretory System

Maintaining a proper water balance in the body is important to avoid dehydration or over-hydration (hyponatremia). The water concentration of the body is monitored by osmoreceptors in the hypothalamus, which detect the concentration of electrolytes in the extracellular fluid. The concentration of electrolytes in the blood rises when there is water loss caused by excessive perspiration, inadequate water intake, or low blood volume due to blood loss. An increase in blood electrolyte levels results in a neuronal signal being sent from the osmoreceptors in hypothalamic nuclei. The pituitary gland has two components: anterior and posterior. The anterior pituitary is composed of glandular cells that secrete protein hormones. The posterior pituitary is an extension of the hypothalamus. It is composed largely of neurons that are continuous with the hypothalamus.

The hypothalamus produces a polypeptide hormone known as antidiuretic hormone (ADH), which is transported to and released from the posterior pituitary gland. The principal action of ADH is to regulate the amount of water excreted by the kidneys. As ADH (which is also known as vasopressin) causes direct water reabsorption from the kidney tubules, salts and wastes are concentrated in what will eventually be excreted as urine. The hypothalamus controls the mechanisms of ADH secretion, either by regulating blood volume or the concentration of water in the blood. Dehydration or physiological stress can cause an increase of osmolarity above 300 mOsm/L, which in turn, raises ADH secretion and water will be retained, causing an increase in blood pressure. ADH travels in the bloodstream to the kidneys. Once at the kidneys, ADH changes the kidneys to become more permeable to water by temporarily inserting water channels, aquaporins, into the kidney tubules. Water moves out of the kidney tubules through the aquaporins, reducing urine volume. The water is reabsorbed into the capillaries lowering blood osmolarity back toward normal. As blood osmolarity decreases, a negative feedback mechanism reduces osmoreceptor activity in the hypothalamus, and ADH secretion is reduced. ADH release can be reduced by certain substances, including alcohol, which can cause increased urine production and dehydration.

Chronic underproduction of ADH or a mutation in the ADH receptor results in diabetes insipidus. If the posterior pituitary does not release enough ADH, water cannot be retained by the kidneys and is lost as urine. This causes increased thirst, but water taken in is lost again and must be continually consumed. If the condition is not severe, dehydration may not occur, but severe cases can lead to electrolyte imbalances due to dehydration.

Another hormone responsible for maintaining electrolyte concentrations in extracellular fluids is aldosterone, a steroid hormone that is produced by the adrenal cortex. In contrast to ADH, which promotes the reabsorption of water to maintain proper water balance, aldosterone maintains proper water balance by enhancing Na⁺ reabsorption and K⁺ secretion from extracellular fluid of the cells in kidney tubules. Because it is produced in the cortex of the adrenal gland and affects the concentrations of minerals Na⁺ and K⁺, aldosterone is referred to as a mineralocorticoid, a corticosteroid that affects ion and water balance. Aldosterone release is stimulated by a decrease in blood sodium levels, blood volume, or blood pressure, or an increase in blood potassium levels. It also prevents the loss of Na⁺ from sweat, saliva, and gastric juice. The reabsorption of Na⁺ also results in the osmotic reabsorption of water, which alters blood volume and blood pressure.

Aldosterone production can be stimulated by low blood pressure, which triggers a sequence of chemical release, as illustrated in Figure 1. When blood pressure drops, the renin-angiotensin-aldosterone system (RAAS) is activated. Cells in the juxtaglomerular apparatus, which regulates the functions of the nephrons of the kidney, detect this and release renin. Renin, an enzyme, circulates in the blood and reacts with a plasma protein produced by the liver called angiotensinogen. When angiotensinogen is cleaved by renin, it produces angiotensin I, which is then converted into angiotensin II in the lungs. Angiotensin II functions as a hormone and then causes the release of the hormone aldosterone by the adrenal cortex, resulting in increased Na⁺ reabsorption, water retention, and an increase in blood pressure. Angiotensin II in addition to being a potent vasoconstrictor also causes an increase in ADH and increased thirst, both of which help to raise blood pressure.

Figure 1. ADH and aldosterone increase blood pressure and volume. Angiotensin II stimulates release of these hormones. Angiotensin II, in turn, is formed when renin cleaves angiotensin. (credit: modification of work by Mikael Häggström)

Hormonal Regulation of the Reproductive System

Regulation of the reproductive system is a process that requires the action of hormones from the pituitary gland, the adrenal cortex, and the gonads. During puberty in both males and females, the hypothalamus produces gonadotropin-releasing hormone (GnRH), which stimulates the production and release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. These hormones regulate the gonads (testes in males and ovaries in females) and therefore are called gonadotropins. In both males and females, FSH stimulates gamete production and LH stimulates production of hormones by the gonads. An increase in gonad hormone levels inhibits GnRH production through a negative feedback loop.

Regulation of the Male Reproductive System

In males, FSH stimulates the maturation of sperm cells. FSH production is inhibited by the hormone inhibin, which is released by the testes. LH stimulates production of the sex hormones (androgens) by the interstitial cells of the testes and therefore is also called interstitial cell-stimulating hormone.

The most widely known androgen in males is testosterone. Testosterone promotes the production of sperm and masculine characteristics. The adrenal cortex also produces small amounts of testosterone precursor, although the role of this additional hormone production is not fully understood.

The Dangers of Synthetic Hormones

Figure 2. Professional baseball player Jason Giambi publically admitted to, and apologized for, his use of anabolic steroids supplied by a trainer.(credit: Bryce Edwards)

Some athletes attempt to boost their performance by using artificial hormones that enhance muscle performance. Anabolic steroids, a form of the male sex hormone testosterone, are one of the most widely known performance-enhancing drugs. Steroids are used to help build muscle mass. Other hormones that are used to enhance athletic performance include erythropoietin, which triggers the production of red blood cells, and human growth hormone, which can help in building muscle mass. Most performance enhancing drugs are illegal for non-medical purposes. They are also banned by national and international governing bodies including the International Olympic Committee, the U.S. Olympic Committee, the National Collegiate Athletic Association, the Major League Baseball, and the National Football League.

The side effects of synthetic hormones are often significant and non-reversible, and in some cases, fatal. Androgens produce several complications such as liver dysfunctions and liver tumors, prostate gland enlargement, difficulty urinating, premature closure of epiphyseal cartilages, testicular atrophy, infertility, and immune system depression. The physiological strain caused by these substances is often greater than what the body can handle, leading to unpredictable and dangerous effects and linking their use to heart attacks, strokes, and impaired cardiac function.

Regulation of the Female Reproductive System

Figure 3. Hormonal regulation of the female reproductive system involves hormones from the hypothalamus, pituitary, and ovaries.

In females, FSH stimulates development of egg cells, called ova, which develop in structures called follicles. Follicle cells produce the hormone inhibin, which inhibits FSH production. LH also plays a role in the development of ova, induction of ovulation, and stimulation of estradiol and progesterone production by the ovaries, as illustrated in Figure 3.

Estradiol and progesterone are steroid hormones that prepare the body for pregnancy. Estradiol produces secondary sex characteristics in females, while both estradiol and progesterone regulate the menstrual cycle.

In addition to producing FSH and LH, the anterior portion of the pituitary gland also produces the hormone prolactin (PRL) in females. Prolactin stimulates the production of milk by the mammary glands following childbirth. Prolactin levels are regulated by the hypothalamic hormones prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH), which is now known to be dopamine. PRH stimulates the release of prolactin and PIH inhibits it.

The posterior pituitary releases the hormone oxytocin, which stimulates uterine contractions during childbirth. The uterine smooth muscles are not very sensitive to oxytocin until late in pregnancy when the number of oxytocin receptors in the uterus peaks. Stretching of tissues in the uterus and cervix stimulates oxytocin release during childbirth. Contractions increase in intensity as blood levels of oxytocin rise via a positive feedback mechanism until the birth is complete.

Oxytocin also stimulates the contraction of myoepithelial cells around the milk-producing mammary glands. As these cells contract, milk is forced from the secretory alveoli into milk ducts and is ejected from the breasts in milk ejection (“let-down”) reflex. Oxytocin release is stimulated by the suckling of an infant, which triggers the synthesis of oxytocin in the hypothalamus and its release into circulation at the posterior pituitary.

Hormonal Regulation of Metabolism

Blood glucose levels vary widely over the course of a day as periods of food consumption alternate with periods of fasting. Insulin and glucagon are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels. Additional regulation is mediated by the thyroid hormones.

Regulation of Blood Glucose Levels by Insulin and Glucagon

Cells of the body require nutrients in order to function, and these nutrients are obtained through feeding. In order to manage nutrient intake, storing excess intake and utilizing reserves when necessary, the body uses hormones to moderate energy stores. Insulin is produced by the beta cells of the pancreas, which are stimulated to release insulin as blood glucose levels rise (for example, after a meal is consumed). Insulin lowers blood glucose levels by enhancing the rate of glucose uptake and utilization by target cells, which use glucose for ATP production. It also stimulates the liver to convert glucose to glycogen, which is then stored by cells for later use. Insulin also increases glucose transport into certain cells, such as muscle cells and the liver. This results from an insulin-mediated increase in the number of glucose transporter proteins in cell membranes, which remove glucose from circulation by facilitated diffusion. As insulin binds to its target cell via insulin receptors and signal transduction, it triggers the cell to incorporate glucose transport proteins into its membrane. This allows glucose to enter the cell, where it can be used as an energy source. However, this does not occur in all cells: some cells, including those in the kidneys and brain, can access glucose without the use of insulin. Insulin also stimulates the conversion of glucose to fat in adipocytes and the synthesis of proteins. These actions mediated by insulin cause blood glucose concentrations to fall, called a hypoglycemic “low sugar” effect, which inhibits further insulin release from beta cells through a negative feedback loop.

This animation describe the role of insulin and the pancreas in diabetes.

Figure 4. The main symptoms of diabetes are shown. (credit: modification of work by Mikael Häggström)

Impaired insulin function can lead to a condition called diabetes mellitus, the main symptoms of which are illustrated in Figure 4. This can be caused by low levels of insulin production by the beta cells of the pancreas, or by reduced sensitivity of tissue cells to insulin. This prevents glucose from being absorbed by cells, causing high levels of blood glucose, or hyperglycemia (high sugar). High blood glucose levels make it difficult for the kidneys to recover all the glucose from nascent urine, resulting in glucose being lost in urine. High glucose levels also result in less water being reabsorbed by the kidneys, causing high amounts of urine to be produced; this may result in dehydration. Over time, high blood glucose levels can cause nerve damage to the eyes and peripheral body tissues, as well as damage to the kidneys and cardiovascular system. Oversecretion of insulin can cause hypoglycemia, low blood glucose levels. This causes insufficient glucose availability to cells, often leading to muscle weakness, and can sometimes cause unconsciousness or death if left untreated.

When blood glucose levels decline below normal levels, for example between meals or when glucose is utilized rapidly during exercise, the hormone glucagon is released from the alpha cells of the pancreas. Glucagon raises blood glucose levels, eliciting what is called a hyperglycemic effect, by stimulating the breakdown of glycogen to glucose in skeletal muscle cells and liver cells in a process called glycogenolysis. Glucose can then be utilized as energy by muscle cells and released into circulation by the liver cells. Glucagon also stimulates absorption of amino acids from the blood by the liver, which then converts them to glucose. This process of glucose synthesis is called gluconeogenesis. Glucagon also stimulates adipose cells to release fatty acids into the blood. These actions mediated by glucagon result in an increase in blood glucose levels to normal homeostatic levels. Rising blood glucose levels inhibit further glucagon release by the pancreas via a negative feedback mechanism. In this way, insulin and glucagon work together to maintain homeostatic glucose levels, as shown in Figure 5.

Figure 5. Insulin and glucagon regulate blood glucose levels.

Practice Question

Pancreatic tumors may cause excess secretion of glucagon. Type I diabetes results from the failure of the pancreas to produce insulin. Which of the following statement about these two conditions is true?

1. A pancreatic tumor and type I diabetes will have the opposite effects on blood sugar levels.
2. A pancreatic tumor and type I diabetes will both cause hyperglycemia.
3. A pancreatic tumor and type I diabetes will both cause hypoglycemia.
4. Both pancreatic tumors and type I diabetes result in the inability of cells to take up glucose.

Show Answer

Statement b is true.

Regulation of Blood Glucose Levels by Thyroid Hormones

The basal metabolic rate, which is the amount of calories required by the body at rest, is determined by two hormones produced by the thyroid gland: thyroxine, also known as tetraiodothyronine or T₄, and triiodothyronine, also known as T₃. These hormones affect nearly every cell in the body except for the adult brain, uterus, testes, blood cells, and spleen. They are transported across the plasma membrane of target cells and bind to receptors on the mitochondria resulting in increased ATP production. In the nucleus, T₃ and T₄activate genes involved in energy production and glucose oxidation. This results in increased rates of metabolism and body heat production, which is known as the hormone’s calorigenic effect.

T₃ and T₄ release from the thyroid gland is stimulated by thyroid-stimulating hormone (TSH), which is produced by the anterior pituitary. TSH binding at the receptors of the follicle of the thyroid triggers the production of T₃ and T₄ from a glycoprotein called thyroglobulin. Thyroglobulin is present in the follicles of the thyroid, and is converted into thyroid hormones with the addition of iodine. Iodine is formed from iodide ions that are actively transported into the thyroid follicle from the bloodstream. A peroxidase enzyme then attaches the iodine to the tyrosine amino acid found in thyroglobulin. T₃ has three iodine ions attached, while T₄ has four iodine ions attached. T₃ and T₄ are then released into the bloodstream, with T₄ being released in much greater amounts than T₃. As T₃is more active than T₄ and is responsible for most of the effects of thyroid hormones, tissues of the body convert T₄ to T₃ by the removal of an iodine ion. Most of the released T₃ and T₄ becomes attached to transport proteins in the bloodstream and is unable to cross the plasma membrane of cells. These protein-bound molecules are only released when blood levels of the unattached hormone begin to decline. In this way, a week’s worth of reserve hormone is maintained in the blood. Increased T₃ and T₄ levels in the blood inhibit the release of TSH, which results in lower T₃ and T₄ release from the thyroid.

The follicular cells of the thyroid require iodides (anions of iodine) in order to synthesize T₃ and T₄. Iodides obtained from the diet are actively transported into follicle cells resulting in a concentration that is approximately 30 times higher than in blood. The typical diet in North America provides more iodine than required due to the addition of iodide to table salt. Inadequate iodine intake, which occurs in many developing countries, results in an inability to synthesize T₃ and T₄ hormones. The thyroid gland enlarges in a condition called goiter, which is caused by overproduction of TSH without the formation of thyroid hormone. Thyroglobulin is contained in a fluid called colloid, and TSH stimulation results in higher levels of colloid accumulation in the thyroid. In the absence of iodine, this is not converted to thyroid hormone, and colloid begins to accumulate more and more in the thyroid gland, leading to goiter.

Disorders can arise from both the underproduction and overproduction of thyroid hormones. Hypothyroidism, underproduction of the thyroid hormones, can cause a low metabolic rate leading to weight gain, sensitivity to cold, and reduced mental activity, among other symptoms. In children, hypothyroidism can cause cretinism, which can lead to mental retardation and growth defects. Hyperthyroidism, the overproduction of thyroid hormones, can lead to an increased metabolic rate and its effects: weight loss, excess heat production, sweating, and an increased heart rate. Graves’ disease is one example of a hyperthyroid condition.

Hormonal Control of Blood Calcium Levels

Regulation of blood calcium concentrations is important for generation of muscle contractions and nerve impulses, which are electrically stimulated. If calcium levels get too high, membrane permeability to sodium decreases and membranes become less responsive. If calcium levels get too low, membrane permeability to sodium increases and convulsions or muscle spasms can result.

Figure 6. Parathyroid hormone (PTH) is released in response to low blood calcium levels. It increases blood calcium levels by targeting the skeleton, the kidneys, and the intestine. (credit: modification of work by Mikael Häggström)

Blood calcium levels are regulated by parathyroid hormone (PTH), which is produced by the parathyroid glands, as illustrated in Figure 6. PTH is released in response to low blood Ca²⁺ levels. PTH increases Ca²⁺ levels by targeting the skeleton, the kidneys, and the intestine. In the skeleton, PTH stimulates osteoclasts, which causes bone to be reabsorbed, releasing Ca²⁺ from bone into the blood. PTH also inhibits osteoblasts, reducing Ca²⁺ deposition in bone. In the intestines, PTH increases dietary CA²⁺ absorption, and in the kidneys, PTH stimulates reabsorption of the CA²⁺. While PTH acts directly on the kidneys to increase Ca²⁺ reabsorption, its effects on the intestine are indirect. PTH triggers the formation of calcitriol, an active form of vitamin D, which acts on the intestines to increase absorption of dietary calcium. PTH release is inhibited by rising blood calcium levels.

Hyperparathyroidism results from an overproduction of parathyroid hormone. This results in excessive calcium being removed from bones and introduced into blood circulation, producing structural weakness of the bones, which can lead to deformation and fractures, plus nervous system impairment due to high blood calcium levels. Hypoparathyroidism, the underproduction of PTH, results in extremely low levels of blood calcium, which causes impaired muscle function and may result in tetany (severe sustained muscle contraction).

The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys. This results in calcium being added to the bones to promote structural integrity. Calcitonin is most important in children (when it stimulates bone growth), during pregnancy (when it reduces maternal bone loss), and during prolonged starvation (because it reduces bone mass loss). In healthy nonpregnant, unstarved adults, the role of calcitonin is unclear.

Hormonal Regulation of Growth

Hormonal regulation is required for the growth and replication of most cells in the body. Growth hormone (GH), produced by the anterior portion of the pituitary gland, accelerates the rate of protein synthesis, particularly in skeletal muscle and bones. Growth hormone has direct and indirect mechanisms of action. The first direct action of GH is stimulation of triglyceride breakdown (lipolysis) and release into the blood by adipocytes. This results in a switch by most tissues from utilizing glucose as an energy source to utilizing fatty acids. This process is called a glucose-sparing effect. In another direct mechanism, GH stimulates glycogen breakdown in the liver; the glycogen is then released into the blood as glucose. Blood glucose levels increase as most tissues are utilizing fatty acids instead of glucose for their energy needs. The GH mediated increase in blood glucose levels is called a diabetogenic effect because it is similar to the high blood glucose levels seen in diabetes mellitus.

Figure 7. Growth hormone directly accelerates the rate of protein synthesis in skeletal muscle and bones. Insulin-like growth factor 1 (IGF-1) is activated by growth hormone and also allows formation of new proteins in muscle cells and bone. (credit: modification of work by Mikael Häggström)

The indirect mechanism of GH action is mediated by insulin-like growth factors (IGFs) or somatomedins, which are a family of growth-promoting proteins produced by the liver, which stimulates tissue growth. IGFs stimulate the uptake of amino acids from the blood, allowing the formation of new proteins, particularly in skeletal muscle cells, cartilage cells, and other target cells, as shown in Figure 7. This is especially important after a meal, when glucose and amino acid concentration levels are high in the blood. GH levels are regulated by two hormones produced by the hypothalamus. GH release is stimulated by growth hormone-releasing hormone (GHRH) and is inhibited by growth hormone-inhibiting hormone (GHIH), also called somatostatin.

A balanced production of growth hormone is critical for proper development. Underproduction of GH in adults does not appear to cause any abnormalities, but in children it can result in pituitary dwarfism, in which growth is reduced. Pituitary dwarfism is characterized by symmetric body formation. In some cases, individuals are under 30 inches in height. Oversecretion of growth hormone can lead to gigantism in children, causing excessive growth. In some documented cases, individuals can reach heights of over eight feet. In adults, excessive GH can lead to acromegaly, a condition in which there is enlargement of bones in the face, hands, and feet that are still capable of growth.

Hormonal Regulation of Stress

When a threat or danger is perceived, the body responds by releasing hormones that will ready it for the “fight-or-flight” response. The effects of this response are familiar to anyone who has been in a stressful situation: increased heart rate, dry mouth, and hair standing up.

Fight-or-Flight Response

Interactions of the endocrine hormones have evolved to ensure the body’s internal environment remains stable. Stressors are stimuli that disrupt homeostasis. The sympathetic division of the vertebrate autonomic nervous system has evolved the fight-or-flight response to counter stress-induced disruptions of homeostasis. In the initial alarm phase, the sympathetic nervous system stimulates an increase in energy levels through increased blood glucose levels. This prepares the body for physical activity that may be required to respond to stress: to either fight for survival or to flee from danger.

However, some stresses, such as illness or injury, can last for a long time. Glycogen reserves, which provide energy in the short-term response to stress, are exhausted after several hours and cannot meet long-term energy needs. If glycogen reserves were the only energy source available, neural functioning could not be maintained once the reserves became depleted due to the nervous system’s high requirement for glucose. In this situation, the body has evolved a response to counter long-term stress through the actions of the glucocorticoids, which ensure that long-term energy requirements can be met. The glucocorticoids mobilize lipid and protein reserves, stimulate gluconeogenesis, conserve glucose for use by neural tissue, and stimulate the conservation of salts and water. The mechanisms to maintain homeostasis that are described here are those observed in the human body. However, the fight-or-flight response exists in some form in all vertebrates.

The sympathetic nervous system regulates the stress response via the hypothalamus. Stressful stimuli cause the hypothalamus to signal the adrenal medulla (which mediates short-term stress responses) via nerve impulses, and the adrenal cortex, which mediates long-term stress responses, via the hormone adrenocorticotropic hormone (ACTH), which is produced by the anterior pituitary.

Short-Term Stress Response

When presented with a stressful situation, the body responds by calling for the release of hormones that provide a burst of energy. The hormones epinephrine (also known as adrenaline) and norepinephrine (also known as noradrenaline) are released by the adrenal medulla. How do these hormones provide a burst of energy? Epinephrine and norepinephrine increase blood glucose levels by stimulating the liver and skeletal muscles to break down glycogen and by stimulating glucose release by liver cells. Additionally, these hormones increase oxygen availability to cells by increasing the heart rate and dilating the bronchioles. The hormones also prioritize body function by increasing blood supply to essential organs such as the heart, brain, and skeletal muscles, while restricting blood flow to organs not in immediate need, such as the skin, digestive system, and kidneys. Epinephrine and norepinephrine are collectively called catecholamines.

Watch this Discovery Channel animation describing the flight-or-flight response.

Long-Term Stress Response

Long-term stress response differs from short-term stress response. The body cannot sustain the bursts of energy mediated by epinephrine and norepinephrine for long times. Instead, other hormones come into play. In a long-term stress response, the hypothalamus triggers the release of ACTH from the anterior pituitary gland. The adrenal cortex is stimulated by ACTH to release steroid hormones called corticosteroids. Corticosteroids turn on transcription of certain genes in the nuclei of target cells. They change enzyme concentrations in the cytoplasm and affect cellular metabolism. There are two main corticosteroids: glucocorticoids such as cortisol, and mineralocorticoids such as aldosterone. These hormones target the breakdown of fat into fatty acids in the adipose tissue. The fatty acids are released into the bloodstream for other tissues to use for ATP production. The glucocorticoidsprimarily affect glucose metabolism by stimulating glucose synthesis. Glucocorticoids also have anti-inflammatory properties through inhibition of the immune system. For example, cortisone is used as an anti-inflammatory medication; however, it cannot be used long term as it increases susceptibility to disease due to its immune-suppressing effects.

Mineralocorticoids function to regulate ion and water balance of the body. The hormone aldosterone stimulates the reabsorption of water and sodium ions in the kidney, which results in increased blood pressure and volume.

Hypersecretion of glucocorticoids can cause a condition known as Cushing’s disease, characterized by a shifting of fat storage areas of the body. This can cause the accumulation of adipose tissue in the face and neck, and excessive glucose in the blood. Hyposecretion of the corticosteroids can cause Addison’s disease, which may result in bronzing of the skin, hypoglycemia, and low electrolyte levels in the blood.

In Summary: Hormonal Regulation of the Reproductive System

Water levels in the body are controlled by antidiuretic hormone (ADH), which is produced in the hypothalamus and triggers the reabsorption of water by the kidneys. Underproduction of ADH can cause diabetes insipidus. Aldosterone, a hormone produced by the adrenal cortex of the kidneys, enhances Na⁺ reabsorption from the extracellular fluids and subsequent water reabsorption by diffusion. The renin-angiotensin-aldosterone system is one way that aldosterone release is controlled.

The reproductive system is controlled by the gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are produced by the pituitary gland. Gonadotropin release is controlled by the hypothalamic hormone gonadotropin-releasing hormone (GnRH). FSH stimulates the maturation of sperm cells in males and is inhibited by the hormone inhibin, while LH stimulates the production of the androgen testosterone. FSH stimulates egg maturation in females, while LH stimulates the production of estrogens and progesterone. Estrogens are a group of steroid hormones produced by the ovaries that trigger the development of secondary sex characteristics in females as well as control the maturation of the ova. In females, the pituitary also produces prolactin, which stimulates milk production after childbirth, and oxytocin, which stimulates uterine contraction during childbirth and milk let-down during suckling.

Insulin is produced by the pancreas in response to rising blood glucose levels and allows cells to utilize blood glucose and store excess glucose for later use. Diabetes mellitus is caused by reduced insulin activity and causes high blood glucose levels, or hyperglycemia. Glucagon is released by the pancreas in response to low blood glucose levels and stimulates the breakdown of glycogen into glucose, which can be used by the body. The body’s basal metabolic rate is controlled by the thyroid hormones thyroxine (T₄) and triiodothyronine (T₃). The anterior pituitary produces thyroid stimulating hormone (TSH), which controls the release of T₃ and T₄ from the thyroid gland. Iodine is necessary in the production of thyroid hormone, and the lack of iodine can lead to a condition called goiter.

Check Your Understanding

Answer the question(s) below to see how well you understand the topics covered in the previous section. This short quiz does not count toward your grade in the class, and you can retake it an unlimited number of times.

Use this quiz to check your understanding and decide whether to (1) study the previous section further or (2) move on to the next section.

Nutrition That Regulates Body Functions: Protein, Vitamins and Water | Healthy Eating

By Sylvie Tremblay Updated December 02, 2018

A balanced diet proves essential for good health because it provides nutrients your body relies on to function properly but can’t produce on its own. Some nutrients — for example, carbohydrates and fats — serve primarily as sources of fuel for your tissues, providing energy you need to get through the day. Other nutrients, including protein, vitamins and water, play other physiological roles in your health, and getting enough of them in your diet helps your cells function.

Amino Acids and Protein

Protein plays a key role in your body’s functioning because it serves as a source of amino acids. Your body uses amino acids to make antibodies — proteins that recognize foreign particles and target them for destruction — as well as hemoglobin, the protein your cells rely on to provide the oxygen they need to function. Protein also regulates your body’s function by helping you synthesize enzymes, a class of proteins tasked with carrying out chemical reactions. Enzymes aid in several cell functions, including energy production and intercellular communication. You need lots of protein each day — the U.S. Department of Agriculture recommends 56 grams daily for men and 46 grams for women.

Water-Soluble Vitamins

Water-soluble vitamins — the group that includes vitamin C, as well as the B-complex vitamins — also support healthy cell functioning. Vitamin C provides structural support for your cells and tissues because it helps make collagen, a fibrous protein that holds tissue together. The B-complex vitamins work in combination to ensure that your cells can access the energy they need to function, by helping you break down carbohydrates and fats. B-complex vitamins also allow you to metabolize protein into amino acids your body can use to maintain healthy cell function.

Fat-Soluble Vitamins

Fat-soluble vitamins — a category made up of vitamins A, E, K and D — also play a role in your body’s ability to function. Vitamin D helps your body use calcium and phosphorus, two minerals you need for healthy bones. Vitamin K helps you synthesize proteins essential for cell function, especially the function of your kidneys. Vitamin A promotes new cell growth and development, which maintains the health of your tissues. Vitamin E supports the function of all your tissues by acting as an antioxidant. This means that it prevents cellular damage, which would otherwise cripple cell function and lead to cell death.

Water

Getting enough water — both from water-rich foods, such as fruits and veggies, and through drinking fluids — keeps your cells and tissues functional. Your body uses water to remove waste products from your cells, helping to prevent an accumulation of toxins that might impede cell function. Water helps transport oxygen and nutrients needed for your cellular metabolism. It also helps you avoid an abnormally high or low body temperature that would hinder enzyme function. Approximately 20 percent of your daily water needs come from food, and you should drink several cups of fluid daily to maintain your body’s water levels — 12 cups daily for men and 9 cups for women.

Nutrients

Nutrients

Nutrients

When food is digested, it breaks down into chemical
substances called nutrients. There are more than 50 known nutrients that keep
the body healthy. Every nutrient is necessary. While each nutrient has a different
job, no nutrient acts alone. Think of nutrients as the “raw materials”
that keep the body alive and healthy. They are responsible for:

• growth,
• repair and maintenance of body parts, and
• regulation of body functions, such as maintaining
  a constant body temperature and circulating fluids throughout the body.

Scientists group nutrients into six major categories:

• Proteins.
• Carbohydrates.
• Fats.
• Water.
• Vitamins.
• Minerals.

Most foods contain more than one of these nutrients,
but no one food contains all the nutrients in the amounts necessary for life.

Ten- and 11-year olds have special nutrient needs
because they are just beginning a growth spurt. In particular, they need more:

• Protein for body growth.
• Calcium for bone growth.
• Iron for muscle development and the increased
  blood volume in their bodies.

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click on the icon to download.
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West Lafayette, Indiana, 47907. All Rights Reserved.

1.1: Introduction to Nutrition – Medicine LibreTexts

Nutrients are substances required by the body to perform its basic functions. Most nutrients must be obtained from our diet, since the human body does not synthesize or produce them. Nutrients have one or more of three basic functions: they provide energy, contribute to body structure, and/or regulate chemical processes in the body. These basic functions allow us to detect and respond to environmental surroundings, move, excrete wastes, respire (breathe), grow, and reproduce.

There are six classes of nutrients required for the body to function and maintain overall health. These are: carbohydrates, lipids, proteins, water, vitamins, and minerals. Nutritious foods provide nutrients for the body. Foods may also contain a variety of non-nutrients. Some non-nutrients such as as antioxidants (found in many plant foods) are beneficial to the body, whereas others such as natural toxins (common in some plant foods) or additives (like certain dyes and preservatives found in processed foods) are potentially harmful.

Macronutrients

Nutrients that are needed in large amounts are called macronutrients. There are three classes of macronutrients: carbohydrates, lipids, and proteins. Macronutrients are carbon-based compounds that can be metabolically processed into cellular energy through changes in their chemical bonds. The chemical energy is converted into cellular energy known as ATP, that is utilized by the body to perform work and conduct basic functions.

The amount of energy a person consumes daily comes primarily from the 3 macronutrients. Food energy is measured in kilocalories. For ease of use, food labels state the amount of energy in food in “calories,” meaning that each calorie is actually multiplied by one thousand to equal a kilocalorie. (Note: Using scientific terminology, “Calorie” (with a capital “C”) is equivalent to a kilocalorie. Therefore: 1 kilocalorie = 1 Calorie – 1000 calories

Water is also a macronutrient in the sense that the body needs it in large amounts, but unlike the other macronutrients, it does not contain carbon or yield energy.

Note: Consuming alcohol also contributes energy (calories) to the diet at 7 kilocalories/gram, so it must be counted in daily energy consumption. However, alcohol is not considered a “nutrient” because it does not contribute to essential body functions and actually contains substances that must broken down and excreted from the body to prevent toxic effects.

Figure \(\PageIndex{2}\): The Macronutrients: Carbohydrates, Lipids, Protein, and Water.

Carbohydrates

Carbohydrates are molecules composed of carbon, hydrogen, and oxygen that provide energy to the body. The major food sources of carbohydrates are milk, grains, fruits, and starchy vegetables, like potatoes. Non-starchy vegetables also contain carbohydrates, but in lesser quantities. Carbohydrates are broadly classified into two forms based on their chemical structure: simple carbohydrates (often called simple sugars) and complex carbohydrates.

Simple carbohydrates consist of one or two basic sugar units linked together. Their scientific names are “monosaccharides” (1 sugar unit) and disaccharides (2 sugar units). They are broken down and absorbed very quickly in the digestive tract and provide a fast burst of energy to the body. Examples of simple sugars include the disaccharide sucrose, the type of sugar you would have in a bowl on the breakfast table, and the monosaccharide glucose, the most common type of fuel for most organisms including humans. Glucose is the primary sugar that circulates in blood to provide energy to cells. The terms “blood sugar” and “blood glucose” can be substituted for each other.

Complex carbohydrates are long chains of sugars units that can link in a straight chair or a branched chain. During digestion, the body breaks down digestible complex carbohydrates into simple sugars, mostly glucose. Glucose is then absorbed into the bloodstream and transported to all our cells where it is stored, used to make energy, or used to build macromolecules. Fiber is also a complex carbohydrate, but it cannot be broken down by digestive enzymes in the human intestine. As a result, it passes through the digestive tract undigested unless the bacteria that inhabit the colon or large intestine break it down.

One gram of digestible carbohydrates yields 4 kilocalories of energy for the cells in the body to perform work. In addition to providing energy and serving as building blocks for bigger macromolecules, carbohydrates are essential for proper functioning of the nervous system, heart, and kidneys. As mentioned, glucose can be stored in the body for future use. In humans, the storage molecule of carbohydrates is called glycogen, and in plants, it is known as starch. Glycogen and starch are complex carbohydrates.

Lipids

Lipids are also a family of molecules composed of carbon, hydrogen, and oxygen, but unlike carbohydrates, they are insoluble in water. Lipids are found predominantly in butter, oils, meats, dairy products, nuts, and seeds, and in many processed foods. The three main types of lipids are triglycerides (triacylglycerols), phospholipids, and sterols. The main job of triacylglycerols is to provide or store energy. Lipids provide more energy per gram than carbohydrates (9 kilocalories per gram of lipids versus 4 kilocalories per gram of carbohydrates). In addition to energy storage, lipids serve as a major component of cell membranes, surround and protect organs (in fat-storing tissues), provide insulation to aid in temperature regulation. Phospholipds and sterols have a somewhat different chemical structure and are used to regulate many other functions in the body.

Proteins

Proteins are macromolecules composed of chains of basic subunits called amino acids. Amino acids are composed of carbon, oxygen, hydrogen, and nitrogen. Food sources of proteins include meats, dairy products, seafood, and a variety of different plant-based foods, most notably soy. The word protein comes from a Greek word meaning “of primary importance,” which is an apt description of these macronutrients; they are also known colloquially as the “workhorses” of life. Proteins provide the basic structure to bones, muscles and skin, enzymes and hormones and play a role in conducting most of the chemical reactions that take place in the body. Scientists estimate that greater than one-hundred thousand different proteins exist within the human body. The genetic codes in DNA are basically protein recipes that determine the order in which 20 different amino acids are bound together to make thousands of specific proteins. Because amino acids contain carbon, they can be used by the body for energy and supply 4 kilocalories of energy per gram; however providing energy is not protein’s most important function.

Water

There is one other nutrient that we must have in large quantities: water. Water does not contain carbon, but is composed of two hydrogen atoms and one oxygen atom per molecule of water. More than 60 percent of your total body weight is water. Without water, nothing could be transported in or out of the body, chemical reactions would not occur, organs would not be cushioned, and body temperature would widely fluctuate. On average, an adult consumes just over two liters of water per day from both eating foods and drinking liquids. Since water is so critical for life’s basic processes, total water intake and output is supremely important. This topic will be explored in detail in Chapter 4.

Micronutrients

Micronutrients are also essential for carrying out bodily functions, but they are required by the body in lesser amounts. Micronutrients include all the essential minerals and vitamins. There are sixteen essential minerals and thirteen essential vitamins (See Table \(\PageIndex{1}\) and Table \(\PageIndex{2}\) for a complete list and their major functions).

In contrast to carbohydrates, lipids, and proteins, micronutrients are not sources of energy (calories) for the body. Instead they play a role as cofactors or components of enzymes (i.e., coenzymes) that facilitate chemical reactions in the body. They are involved in all aspects of body functions from producing energy, to digesting nutrients, to building macromolecules. Micronutrients play many essential roles in the body.

Minerals

Minerals are solid inorganic substances that form crystals and are classified depending on how much of them we need. Trace minerals, such as molybdenum, selenium, zinc, iron, and iodine, are only required in a few milligrams or less. Macrominerals, such as calcium, magnesium, potassium, sodium, and phosphorus, are required in hundreds of milligrams. Many minerals are critical for enzyme function, while others are used to maintain fluid balance, build bone tissue, synthesize hormones, transmit nerve impulses, contract and relax muscles, and protect against harmful free radicals in the body that can cause health problems such as cancer.

Vitamins

The thirteen vitamins are categorized as either water-soluble or fat-soluble. The water-soluble vitamins are vitamin C and all the B vitamins, which include thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate and cobalamin. The fat-soluble vitamins are A, D, E, and K. Vitamins are required to perform many functions in the body such as assisting in energy production, making red blood cells, synthesizing bone tissue, and supporting normal vision, nervous system function, and immune system function.

Vitamin deficiencies can cause severe health problems and even death. For example, a deficiency in niacin causes a disease called pellagra, which was common in the early twentieth century in some parts of America. The common signs and symptoms of pellagra are known as the “4D’s—diarrhea, dermatitis, dementia, and death.” Until scientists discovered that better diets relieved the signs and symptoms of pellagra, many people with the disease ended up hospitalized in insane asylums awaiting death. Other vitamins were also found to prevent certain disorders and diseases such as scurvy (vitamin C), night blindness (vitamin A), and rickets (vitamin D).

Chapter 11: Nutrients that Promote Growth and Regulate Body Functions (Vitamins, Minerals and Water) – HLT 111 – Health and the Young Child – Textbook

Chapter 11: Nutrients that Promote Growth and Regulate Body Functions (Vitamins, Minerals and Water)​

Chapter Objectives

     At the conclusion of this chapter, students will be able to

1. Identify fat soluble and water soluble vitamins
2. Describe the role of vitamins in regulations of growth and body functions
3. Describe the role of minerals in regulation of various body functions
4.  Describe water and mineral balance and the health consequences of excesses and deficiencies of some of the minerals, vitamins.

Overview

Micronutrients

Vitamins are organic compounds obtained mostly from outside the body. Vitamins do not provide energy. There are two broad categories of vitamins:

• Fat soluble: Dissolve in lipids, can be stored, not needed daily (e.g., vitamins A, D, E, K)
• Water soluble: Dissolve in water, absorbed into bloodstream immediately, needed daily

Fruits, dark leafy vegetables and animal products are good sources of vitamins.  Deficiencies in vitamins may lead to specific diseases. For example rickets (vitamin D deficiency), scurvy ( vitamin C deficiency), anemia ( folic acid deficiency), night blindness ( vitamin A deficiency).

Minerals are inorganic compounds not synthesized by the body; They are needed in very small quantities but possibly essential. Minerals are important for biochemical processes and formation of cells and tissues. Both plant and animal products are good sources of minerals. Deficiencies in minerals are associated with specific diseases. For example,  anemia (Iron deficiency), goiter (iodine deficiency), and bone and teeth conditions ( calcium deficiency).

Water

Water is  the main component of the body (60 percent of body mass) . Water is needed for digestion, absorption, and other body functions. Water is regularly lost through sweating, excretion, and breathing

• Approximately 1,000 ml (4−8 cups) needed each day. Inadequate fluid intake or excessive fluid loss as in diarrhea leads to dehydration. Excess water or fluid intake, especially in the young child may cause over hydration or water intoxication.

How the Body Regulates Heat

A close look at the complex systems that keep us functioning can inspire awe. Such is the case with the body’s complicated temperature-regulating mechanism.

This intricate apparatus balances heat production with heat loss, keeping the body at a temperature just right for optimal function. This balancing act is directed automatically and seamlessly by the hypothalamus, a small portion of the brain that serves as the command center for numerous bodily functions, including the coordination of the autonomic nervous system.

Much like a thermostat regulates the temperature inside your home, the hypothalamus regulates your body temperature, responding to internal and external stimuli and making adjustments to keep the body within one or two degrees of 98.6 degrees.

Systematized

But unlike a thermostat, which simply turns the heat or air conditioning on or off until a desired temperature is reached, the hypothalamus must regulate and fine-tune a complex set of temperature-control activities. It not only helps to balance body fluids and maintain salt concentrations, it also controls the release of chemicals and hormones related to temperature.

The hypothalamus works with other parts of the body’s temperature-regulating system, such as the skin, sweat glands and blood vessels — the vents, condensers and heat ducts of your body’s heating and cooling system.

The middle layer of the skin, or dermis, stores most of the body’s water. When heat activates sweat glands, these glands bring that water, along with the body’s salt, to the surface of the skin as sweat. Once on the surface, the water evaporates. Water evaporating from the skin cools the body, keeping its temperature in a healthy range.

Sensitive

In a related function, blood vessels react to the introduction of outside organisms, such as bacteria, and to internal hormone and chemical changes by expanding and contracting. These actions move blood and heat closer to or farther from the skin, thus releasing or conserving warmth.

When all parts of the body’s heat-regulating mechanism operate smoothly, body temperature stays near 98.6 degrees. However, there are times when body temperature can go awry.

Heatstroke | Hot flashes | Fever

Heatstroke

On most days, the hypothalamus reacts to increases in outdoor temperature by sending messages to the blood vessels, telling them to dilate. This sends warm blood, fluids and salts to the skin, setting off the process of evaporation.

“Problems occur when a person is in the heat for a long time or in such extremes of heat or humidity that the evaporation process fails,” says Edward Ward, MD, director of the emergency department at Rush University Medical Center.

In prolonged heat exposure, the body sweats so much that it depletes itself of fluids and salts, leaving nothing to sustain the evaporation process. When this process ceases, body temperature soars and heat illnesses may result — including the most serious: heatstroke. 

How you know it’s heatstroke: Look for the following symptoms:

• A body temperature above 103 degrees
• Red, hot, dry skin
• A rapid, strong heartbeat
• A throbbing headache
• Dizziness 
• Nausea 
• Confusion 
• Unconsciousness

Getting help for heatstroke: Heatstroke is a life-threatening emergency. If you have these symptoms, you need to cool down quickly while you or someone else calls for help.

“One of the most effective ways to cool down is to spray or douse your body with water and sit by a fan to kick-start the evaporation process,” Ward says. “This will help decrease your temperature while you are waiting for medical assistance.”

An ounce of prevention: Because heatstroke is so serious, Ward strongly advises focusing on prevention. This is especially true for people age 65 and older, who are at higher risk for heat illness simply because the regulating mechanism becomes less effective with time.

Additionally, cardiovascular and neurological conditions increase a person’s risk for heatstroke, as do medications that interfere with the body’s ability to sweat properly, such as antipsychotics and antispasmodics.

People who have these conditions or take these types of medications should pay special attention to the weather and the heat index — the combination of heat and humidity. If temperatures rise, drink lots of fluids and stay in a cool place.

“If you’re worried or think you’re having problems because of the heat, try to contact your primary care doctor,” Ward says. “But if it’s a real crisis, go to the emergency room. We’d much rather see you sooner than later.”

Hot flashes

The female body has a regular monthly cycle of hormonal ups and downs. During menopause and the years prior to it, this cycle becomes erratic and extreme, with large fluctuations in estrogen levels. The fluctuations of this hormone lead to a complex chain of events that affects the function of the hypothalamus and triggers changes in the blood vessels that increase blood flow.

Blood vessels constrict and then expand rapidly in what is known as vasomotor spasm. These spasms start the chain of events that lead to the skin flushing and temperature changes called hot flashes.

How to tell if you’re having a hot flash: The rise in temperature involved in hot flashes is not severe. During a hot flash, the blood rushing to the vessels nearest the skin may raise skin temperature by five to seven degrees, but core body temperature will not usually rise above a normal 98.6 degrees.

Still, it can feel like an extreme change to the woman having the hot flash.

Plus, hot flashes can cause more than discomfort. They may lead to excessive sweating and can interrupt sleep patterns.

One important reason to see a doctor about hot flashes: Not all of them are related to menopause. There are various things we need to test for to have a complete understanding of where a woman’s health stands.

Getting help for hot flashes: Women may choose to use hormone replacement therapy or take antidepressant medications to ease hot flashes. However, these have side effects that need to be discussed with a doctor.

Treatment for hot flashes can be complicated. That’s why you need to find a doctor you can trust to partner with and create an individual treatment plan.

There’s another important reason to see a doctor about hot flashes: Not all of them are related to menopause. There are various things we need to test for, including hypothyroidism, to have a complete understanding of where a woman’s health stands.

Fever

If your body temperature rises to 99.6 degrees or higher, you have a fever. How does this rise in temperature occur?

“The hypothalamus responds to different factors, such as infectious organisms and injury, by releasing fever-producing chemicals that change body temperature,” says Ward.

Specifically, these chemicals cause blood vessels to narrow and pull heat into the innermost part of the body. The result is a fever. Fever not only signals that a foreign invader has entered the body; it’s also a sign that the body’s immune system is working to combat that invader.

As the body fights off the infection, the fever naturally resolves itself.

When a fever is cause for concern: Fever is rarely dangerous or damaging, Ward says, except in a few cases.

It’s concerning if a person has a fever over 102 or 103 degrees, especially if it lasts more than a couple days or has no obvious cause — meaning it is not accompanied by cold or flu symptoms.

When a fever is cause for alarm: A fever that rises to 105 degrees or higher is especially dangerous. If left untreated, a fever this high can lead to dehydration, dizziness, weakness and confusion.

Getting help for fever: If you have these types of symptoms with a fever, see your doctor as soon as possible.

Your primary care physician is always your best resource for help. Most offices have someone on call 24/7, and many hospitals, including Rush, offer walk-in clinics and same-day primary care appointments. So if you’re concerned about a fever, it’s always a good idea to call or stop in.

Endocrine Hormones

Hormones sent from the hypothalamus to the anterior lobe of the pituitary gland function as signals. They stimulate or inhibit the release of anterior pituitary hormones, which regulate endocrine glands and control a range of body functions. Human growth hormone (hGH) travels to skeletal muscles, bones, and the liver to promote overall growth and development. Thyroid-stimulating hormone (TSH) and adrenocorticotropic hormone (ACTH) target the thyroid and adrenal glands, two primary endocrine glands that regulate metabolism for temperature regulation, growth, and stress resistance. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate sex cell production and reproductive processes in the gonads, and prolactin (PRL) induces milk production in mammary glands.

4. Posterior Pituitary Hormones Regulate Water Levels and Induce Labor

Most hormones secreted by the hypothalamus travel to the anterior lobe of the pituitary, where they stimulate or inhibit the release of other hormones. But two, antidiuretic hormone (ADH or vasopressin) and oxytocin (OXT), are secreted into the posterior pituitary lobe by axonal extensions from the hypothalamus. The posterior pituitary stores ADH and OXT and releases them directly into the bloodstream when needed. ADH acts on the kidneys, blood vessels, and sweat glands in the skin to reduce water loss throughout the body. OXT factors into pregnancy and nurturing. It causes smooth muscle contractions of the uterus to induce birth. Later it stimulates milk ejection from the mammary glands and promotes bonding between mother and child.

5. Hormones Fuel the Body’s Response to New Stimuli and Stress

Hormones control ongoing internal functions. They also enable our body’s reactions to changes in the environment — for example, when we perceive a sudden threat or find ourselves under stress. In this case, the hypothalamus commands the adrenal glands directly (via nervous signals) to ramp up production of epinephrine and norepinephrine. These hormones promote the “fight-or-flight” response: breathing and heart rate increase and our muscles get a burst of energy. If the situation continues, the endocrine system kicks into the “resistance phase”: The hypothalamus directs the pituitary to release adrenocorticotropic hormone (ACTH). The ACTH stimulates the adrenal glands to release mineralocorticoids and glucocorticoids, and the pancreas secretes glucagon. These hormones increase blood sugar and sustain elevated blood flow and energy levels for prolonged stress.

90,000 Brain Areas – Learn more about the different parts of your brain

What is our brain made of? The brain is one of the most complex organs of the human body. It consists of various parts or structures, each of which has its own function, but they work together and in a coordinated manner through the thousands of connections that form between them and all other parts of our body. Below will be shown the structure of the brain, its region and the function of each zone.

The structure of the brain

The Central Nervous System consists of the brain and spinal cord.

• The brain is the main part of the central nervous system and is located in the skull.
• The spinal cord is a long, whitish cord located in the spine that connects the brain to the entire body. It acts as a kind of information highway between the brain and the body, transmitting information from the brain to the body.

So the brain and the brain are not the same thing. To understand the difference between the brain and the brain, one should study how the CNS (central nervous system) of the embryo develops.In general terms, during development , the human brain splits into three different “brains” according to their level of phylogenetic development: the rhomboid brain (rhombencephalon), mesencephalon (“midbrain”), and proencephalon (“forebrain”).

ROMBOID BRAIN: The oldest and least developed brain structure found in all vertebrates. The structure and organization of the diamond-shaped brain is the simplest. Responsible for regulating basic survival functions and controlling movement.Damage to this part of the brain can lead to death or serious damage. It is located in the upper part of the spinal cord and consists of several sections:

• Medulla oblongata or bulb of the brain : helps control automatic functions such as breathing, blood pressure, heart rate, digestion … etc.
• Varoliev bridge or bridge : the part of the brain stem located between the medulla oblongata and midbrain. It connects the spinal cord and medulla oblongata to the upper cortex and / or cerebellum.It controls the automatic functions of the body, as well as regulates consciousness and levels of arousal (anxiety), sleep.
• Cerebellum : Located under the occipital lobes of the cerebral hemispheres, it is the second largest structure in the brain. The cerebellum integrates all the information coming from the senses and the motor area of ​​the brain, and therefore its main function is to control movement. It also controls posture and coordination of movements, which allows us to move, walk, ride a bicycle… Damage to this region leads to problems associated with movement, coordination and postural control, as well as impairments of a number of higher cognitive processes.

MEZENCEPHALON or MEDIUM BRAIN – is a structure that connects the back of the brain with the front, directing motor and sensory impulses between them. Its correct functioning is necessary for the implementation of conscious actions. Injuries to this part of the brain cause a number of movement disorders, such as tremors, rigidity, and strange movements…

FRONT BRAIN or PROZENCEPHALON: is the most developed and evolved part of the brain with the most complex organization. Consists of two main divisions:

• Diencephalon: is located inside the brain and consists of such important structures as the thalamus and hypothalamus.
• Thalamus: is a kind of transmission station of the brain: it transmits most of the perceived sensory signals (visual, auditory and tactile) and makes it possible for them to be processed by other parts of the brain.Also involved in motor control.
• Hypothalamus: is a gland located in the central base of the brain that plays a critical role in regulating emotions and many other bodily functions such as appetite, thirst and sleep.
• Terminal or large brain: is known as the brain covering the entire cerebral cortex (a thin layer of gray matter collected in folds that form the grooves and gyrus), the hippocampus and the basal ganglia.

Anatomy and function of the brain

In this section, we will take a closer look at the anatomy of the brain and the functions of its departments.

BASAL GANGLES: subcortical neural structures responsible for motor functions. They receive information from the cortex and brain stem, process it and re-project it into the cortex, medulla oblongata and the brain stem, ensuring coordination of movements. They consist of several departments:

• The caudate nucleus is a nucleus in the shape of the letter C, involved in the control of conscious movements, as well as in the processes of learning and memory.
• Shell
• Pallidum
• Tonsil, which plays a key role in controlling emotions, especially fear.The amygdala helps to store and classify memories triggered by emotions.

HIPPOCAMP: a small subcrustal structure in the shape of a seahorse. Plays a critical role in the formation of memory – both in the classification of information and in the organization of long-term memory

BRAIN CORTEX: A thin layer of gray matter collected in folds that form grooves and convolutions that give the brain its characteristic appearance. The convolutions are separated by grooves and cerebral grooves, the deepest of which are called slits.The cortex is divided into two hemispheres, right and left, separated by an interhemispheric fissure and interconnected by the corpus callosum, through which information is transmitted from one hemisphere to another. Each hemisphere controls one side of the body, while control is asymmetric: the left hemisphere controls the right side, and the right one controls the left side of the body. This phenomenon is called brain lateralization.

EACH HEMISPHERE, IN ITS SEQUENCE, DIVIDED INTO 4 SHARES: these lobes are limited by four cerebral grooves (central or Roland’s groove, lateral or Sylvian groove, parieto-occipital groove and cingulate groove) 9009:

910000118:

910000118:

18 the largest lobe of the cerebral cortex.Located in front of the skull, behind the forehead. Extends from the front to the Roland furrow. This is the center of command and control of the brain, orchestra conductor. It is closely related to executive functions (Miller, 2000; Miller and Cohen, 2001), i.e. responsible for planning, reasoning, problem solving, judgment, impulse control, as well as regulating emotions such as empathy and generosity, behavior.

Squire, L.R. (1992) Memory and the hippocampus: a synthesis from findings with rats, monkeys and humans. Psychol Rev, 99, pp. 195-231.

Miller, E. K. (2000). The prefrontal cortex and cognitive control. Nat Rev Neurosci, 1 (1), 59-65.

Miller, E. K. y Cohen, J. D. (2001). An integrative theory of prefrontal cortex function. Annu Rev Neurosci, 24, 167-202.

Kosslyn, S.M. (1994) Image and brain: thre resolution of the imaginery debate.Cambridge, Mass; MIT Press.

90,000 what it consists of and how it works

author: Maria Yiallouros, erstellt am: 2016/12/01,
editor: Dr. Natalie Kharina-Welke, Translator: Dr. Natalie Kharina-Welke, Last modified: 2021/01/20

In humans, the nervous system is the highest level system in the body. It consists of various organs. Through them, she interacts with the outside world and at the same time she controls all the work that takes place inside the body.Numerous nerves in the body make up the so-called peripheral nervous system [peripheral nervous system] in humans. The brain and spinal cord are called the central nervous system [CNS].

A part of the nervous system, which is called the autonomic or autonomic nervous system, controls all the work of the body, which cannot be influenced by the will of a person (that is, these actions of the body are not under the sleepy control of a person).

The autonomic nervous system controls all vital basic functions of the body.It works day and night, and controls such spontaneous processes as heartbeat, digestion and breathing, pressure level and bladder function.

When, during physical exertion, a person produces sweat and increases the pulse rate, this is also regulated by the autonomic nervous system.

The autonomic nervous system itself consists of two divisions: the sympathetic nervous system (it can also be called the sympathetic division) and the parasympathetic nervous system (it can also be called the parasympathetic division).Both of these departments regulate the work of the same organs, but in the opposite way:

• The sympathetic nervous system , when there is intense work or the body is in a stressful situation, stimulates the expenditure of energy. For example, it enhances the work of the heart in a person (the pulse quickens), breathing accelerates and blood pressure rises.
• The parasympathetic nervous system , on the contrary, is responsible for ensuring that the body accumulates and restores energy reserves during sleep, rest and rest.For example, it weakens the work of the heart (the heart rate decreases) and stimulates the work of the glands and muscles in the digestive tract.

90,000 Stroke: symptoms and effects

The number of stroke patients only increases from year to year. A stroke occurs as a result of impaired blood circulation in the brain, leading to damage and death of nerve cells. Our brain can be divided into 4 main parts: the right and left hemispheres, the cerebellum, and the brain stem.Each of these parts is responsible for different functions, so the consequences of a stroke directly depend on which part of the brain was damaged.

1. The left hemisphere of the brain
The left hemisphere of the brain is responsible for the motor functions of the right side of the body and language abilities. This hemisphere controls speech, as well as the ability to read and write. A patient with an injury to the left hemisphere will have muscle weakness or paralysis in the right side of the body. In more serious cases, he will be unable to speak and will lose his hearing.

2. Right hemisphere of the brain
The right hemisphere of the brain is responsible for the motor functions of the left side of the body and, the ability to assess the distance and shape and size of objects. Patients in this case will have muscle weakness or paralysis on the left side of the body.

3. Cerebellum
The cerebellum regulates the balance of the body’s system and muscle coordination. The consequences of a stroke in this area of ​​the brain will make the patient dizzy, imbalanced, and vomiting.

4.Brain stem
The brain stem is a structure that connects the brain and spinal cord. It controls the breathing mechanism, blood pressure, and heart rate. Patients may experience muscle weakness in the limbs on one or both sides of the body.

No one is safe from a stroke, but the attack can be avoided and it is treatable. Learn to listen to your body and recognize the initial symptoms: numbness and muscle weakness in the limbs, loss of balance. If you notice these symptoms, see your doctor as soon as possible.If a patient is admitted to the hospital within three hours of a stroke, they have a better chance of successful treatment and full recovery. Physicians and physiotherapists select special treatment and exercise programs for stroke recovery.

If you witness someone falling, fainting or lightheadedness, or someone complains of a sudden severe headache, darkening of the eyes, then ask the victim to do 4 simple things:

• Smile
• Speak
• Stick out tongue
• Raise both hands in front of you.

A crooked smile, slurred speech, a tongue slanted to one side, inability to raise or hold an outstretched arm in a horizontal position are all signs of a stroke. If they are found, provide the victim with peace and immediately call an ambulance. In no case should you give any medications, nitroglycerin and other vasodilators are especially dangerous.

Neurology or Emergency departments can be reached by calling the Call Center at 1719.

90,000 Why do we need kidneys?

The kidneys are essential for our survival. They serve several extremely important functions. Their main tasks are to remove waste products from the blood and maintain a balance of salt and water levels in the body.

The location of your kidneys

Most people have two kidneys, although it is possible to live a normal life with one. The buds are shaped like beans and are about the size of a fist. To determine where the kidneys are, do the following: Place your hands on your hips and slide them up until you feel your ribs with your fingers.The kidneys are located behind the thumbs. You cannot feel them, but they are there, well hidden inside the body.

How Your Kidneys Work

Depending on your weight, 4-6 liters of blood circulates in your body. Blood is transported to and through the kidneys by the renal arteries. Every day, about 1,500 liters of blood pass through the kidneys and are cleaned by about one million microscopic filters. These filters are called nephrons, and they are so small that it takes a microscope to see them.Most kidney diseases are caused by damage to the nephrons. When they lose their filtering properties, dangerous levels of fluids and waste products can develop in the body.

Blood needs to be cleansed

When the body gets the nourishment it needs from the food you eat, some waste products are returned back into the blood. One of the key functions of the kidneys is to continuously remove these waste products from the blood. It can be said that the kidneys are the “cleaning station” of the blood.If the kidneys do not remove waste products, they will accumulate in the blood, causing serious harm to the body.

The kidneys also perform other functions

The kidneys also perform other functions besides blood purification. An important function of the kidneys is to maintain the balance of fluids and minerals in the body.

Exemption from waste products and water

Substances that are filtered by the kidneys, mix with water and turn into urine. Urine is passed from the kidneys through small tubes (ureters) and collected in the bladder.Urine, which contains waste products and water, is excreted from the body through the urethra.

The kidneys always have a job

The kidneys also produce active vitamin D, which is essential for the absorption of calcium from food. Calcium is important for building your bones, among other things. In addition, the kidneys help regulate blood pressure and stimulate red blood cell production. Thus, without a doubt, kidney function is essential for good health.

Ciliary (ciliary) body: description, structure, functions

Ciliary body – what is it?

Ciliary body or Ciliary body is the part of the choroid of the eye, which consists of blood vessels and muscles.Tension or relaxation of these muscles changes the shape of the lens, due to which we can see well both far and near (we accommodate). The blood vessels form special dense plexuses and nourish the iris as well as the ciliary body. The capillaries of the ciliary processes produce intraocular fluid, which in turn regulates intraocular pressure. The body is attached to the prominence of the sclera and serves as a support for the iris of the eye, another component of the choroid.

Structure and function of the ciliary body

The ciliary body is the middle part of the choroid.It is located behind the iris around the circumference of the eyeball and is covered from the outside by the sclera.

The shape of the ciliary body – triangle. Its top protrudes into the eye cavity. The body has two parts: flat, which is adjacent to the dentate line and ciliary, on which the ciliary processes are located. Thus, the jagged line serves as the border between the choroid and the ciliary body.

The ciliary processes are small plates containing networks of blood vessels.They filter blood and form intraocular fluid.

At the cellular level, two layers are distinguished in the ciliary body: mesodermal (muscle and connective tissue) and neuroectodermal (non-functional layers of the epithelium).

The cell layers are located sequentially from the inside: muscle, vascular, basal plate, pigment and non-pigment epithelium, internal border membrane.

The main function of the muscle layer is accommodation, that is, the ability of the eye to focus on objects located at different distances.

The inner surface of the ciliary body is connected to the lens by means of the ciliary girdle. This belt keeps the lens in a normal position and, together with the ciliary muscle, also provides accommodation.

In the body, the posterior, middle and anterior ciliary fibers are secreted. The work of the ciliary muscle – its tension and relaxation – changes the shape of the lens, due to which we see at different distances.

The supply of blood and nutrients to the body is provided by the two posterior ciliary arteries.Also, many nerve endings are suitable for the ciliary body, which ensure its full work.

Symptoms of diseases of the ciliary body

The ciliary body is affected by various eye pathologies, including:

• Iridocyclitis (inflammatory process)
• Formation of tumors
• Dystrophy (characterized by damage to cells and intercellular substance, resulting in changes in the function of the organs of vision)
• Glaucoma (increased intraocular pressure)
• Hypotension (low blood pressure).

With diseases of the ciliary body, the entire visual system suffers. As a rule, with violations of the ciliary body, the following symptoms occur:

• Decreased visual acuity in the distance and near
• Redness of the eyeball
• Blurred vision
• Pain sensations.

Diagnostics and treatment of diseases of the ciliary body

Various methods help to identify diseases of the ciliary body:

• Palpation (light finger pressure on the eyelids)
• Tonography (measurement of intraocular pressure)
• Biomicroscopy (slit lamp examination).
• Ultrasonic biomicroscopy (UBM) (examination with ultrasound)

Treatment of pathologies of the ciliary body is individual in each of their cases and can be carried out in various ways.

If any of the above symptoms appear, we suggest that you undergo a full examination of the organs of vision at the Eye Clinic of Dr. Belikova. We use only high-quality modern equipment and accompany the Patient all the way – from diagnosis to complete recovery.The attending physician will prescribe an effective treatment based on the individual characteristics of your body.

Skin: structure and function of human skin

What is skin
The skin covers our entire body and is the largest human organ. An adult has a skin area of ​​about 2 square meters. Together with subcutaneous adipose tissue, its weight averages 16-17% of the total body weight [3].

It protects our body from the environment, maintaining its homeostasis (self-regulating process).The skin provides natural thermoregulation: prevents overheating or hypothermia of the body. She participates in respiration and metabolic processes.
Our emotions and physical condition are reflected on the skin, as in a mirror.

Skin structure
If we talk about the structure of the skin, then it consists of three main layers: epidermis, dermis and hypodermis (subcutaneous fat).
Let’s take a closer look at the structure of the skin.

Epidermis
Epi is translated from Greek as “over”, dermis – skin.The epidermis is the upper layer of the skin, its thickness is about 0.05-0.1 mm [1].
Four layers are distinguished in the structure of the epidermis [2]:
• basal
• prickly
• granular
• stratum corneum (outer layer)
Every 3-4 weeks the epidermis is renewed. This process begins in the basal (primordial) layer. The cells ascend to the upper stratum corneum, transforming into other types of cells along the way.

Cells on the basement membrane mature and become keratinocytes.Keratinocytes divide and move closer to the outer layer – the stratum corneum. As cells are pushed towards the surface, they become flatter. In the end, they lose their core, die off and turn into scales, of which the stratum corneum consists. Thus, a barrier from the external environment is created. The process of renewal of the stratum corneum is constant, we lose about 40,000 scales per minute. If the skin is healthy, this process is invisible to the eye. [one].

Dermis
Under the epidermis is a deeper layer – the dermis (skin).Its thickness is almost 2 mm. It is represented by connective tissue, which is based on strong protein fibers – collagen and elastin. Collagen makes our skin firm, elastin – elastic.
The dermis contains a complex network of blood and lymphatic vessels, nerve endings, hair follicles, sweat and sebaceous glands are also located in the dermis. In terms of structure, the dermis can be divided into two levels: superficial papillary dermis and deep reticular dermis.

Hypodermis (subcutaneous fatty tissue)
Hypodermis (or subcutis (sub – under, cutis – the name of the dermis and the upper layer of the skin)) is the largest and heaviest layer, without it the skin would weigh 3 kg, and with it it can weigh up to 20 kg [3].
Thanks to the hypodermis, the human body acquires soft features, without it bones and joints would be clearly visible. Loose connective tissue and fat are involved in the structure of this layer. The hypodermis is penetrated by blood vessels and nerve endings, but larger than in the dermis.
Of course, the structure of the skin is much more complex, but these three layers of which the skin is composed represent its main “floors”.

Skin functions
Skin functions are very diverse and each layer has its own tasks.
The epidermis primarily creates a protective barrier and has an acid mantle. It protects against the effects of various harmful substances and allergens, as well as mechanical influences. The protective function of the skin is one of the most important.
Acids on the stratum corneum lower the pH and bind water, keeping the top layer of the skin hydrated. The pH level is important for the skin microbiome – a collection of microorganisms on the surface of the human skin that perform important protective and regulatory functions.
The spiny layer contains Langerhans cells, which are responsible for the immune defense of the skin.Merkel cells are also located in the upper layer and among their functions is to provide skin sensitivity [2].
Even in the epidermis, there are pigment cells, melanocytes, which determine the color of the skin and perform the function of protection from UV rays [2].
The dermis regulates heat transfer from the body. To reduce body temperature, sweat glands move moisture to the surface of the skin. To keep us warm, it reduces blood flow to the skin, which helps to retain heat inside the body.
Thanks to the dermis, our skin is firm and elastic.Here are the hair follicles from which the hair grows.
The blood vessels of the dermis supply the skin with oxygen and nutrients and support the immune system. Nerve endings located in the dermis convey important information to the brain, such as fever or pain.
The hypodermis accumulates and stores nutrients. Subcutaneous fat prevents hypothermia of the body. It creates additional protection for the internal organs.
As you can see, the importance of skin functions to humans cannot be overemphasized.
Skin care

Face
Facial skin care depends on the condition of your skin (sensitivity, sebaceous gland secretions, age-related changes, etc.) and it is better to be picked up by a dermatologist. Basic care includes cleansing, moisturizing and sun protection. Funds are selected individually.

Body
One of the basic rules for skin care is to avoid daily bathing with soap. You can shower every day without harming your skin using water as it has a neutral pH.If you want to use a detergent, it must be odorless, colorless and almost free of foam. Using soap with a high pH, ​​we destroy the protective barrier, and it takes 4 weeks for the epidermis to fully recover.

It is more beneficial for human skin to take a shower than a bath. Since the skin leaches out after a long stay in the bubble bath.
Be careful with different oils. They are harsh cleaning agents and are not suitable for maintenance. Dry eczema may develop on the skin due to the frequent use of the oil.Fat-containing creams, ointments or liposols are much better suited for the moisturizing function [1].

Legs
Do not aggressively remove the stratum corneum, as it protects the soft tissue from compression. Its excess can be removed with a file.
The stratum corneum of the legs may crack and the skin may become rough. To prevent dangerous bacteria from penetrating through cracks in the skin, you can use a greasy ointment. Apply it before bed and wrap your feet in an airtight foil.This procedure will allow the ointment to penetrate even into the stratum corneum [1].

Used literature:
1. Adler J. What hides the skin. 2 square meters that dictate how we live. M .: Publishing house “E”, 2017, p. 13.
2. Bykov V.L. Private histology of a person. 2nd ed. SPb .: SOTIS, 1999, p. 215.
3. Medical encyclopedia. Kozha [Electronic resource] URL: dic.academic.ru/dic.nsf/enc_medicine/14590

90,000 Pediatric endocrinologist who is this? – Virilis

Who is this specialist?

Endocrinologist – specializes in the treatment, diagnosis and prevention of diseases of the endocrine system of babies.Endocrinology is the science that studies these glands, how hormones work, and how the hormonal system works. The endocrine system consists of endocrine glands that secrete hormones – chemicals that regulate the functioning of organs and systems. These include the thyroid gland, pituitary gland, pancreas, adrenal glands, and gonads (gonads). Together, they control the work of the entire child’s body and affect the development and growth of the baby. For example, hormones regulate how a child grows and matures.Endocrine disorders are a diverse group of diseases that affect a child’s growth, development, and sexual function.

It is extremely important to monitor the state of the endocrine system through regular preventive examinations. Most often, a pediatrician directs an appointment with a pediatric endocrinologist, but in our medical center it can be a pediatric gastroenterologist, immunologist or dermatologist. The child’s endocrine system is responsible for the hormonal sphere of the baby’s health, therefore, the correctness of its development and growth largely depends on its condition.Without timely treatment, such pathologies can lead to infertility or dementia in adulthood. Our endocrinologists have extensive training and experience in treating children with endocrine disorders and hormonal problems.

In newborns and infants an endocrinologist is engaged in the detection and treatment of congenital pathologies of the endocrine system, such as dysfunctions of the pituitary gland, problems with determining sexual differentiation, disorders of glucose and calcium metabolism, thyroid diseases.

You can make an appointment with a doctor and get acquainted with the prices on the page: Children’s endocrinologist.

Diseases treated by an endocrinologist in children

Pediatric endocrinologists diagnose and treat the following hormonal disorders:

• Growth retardation,
• Early or delayed puberty,
• Enlarged thyroid gland,
• Hypofunction and hyperfunction of the thyroid gland,
• Hypo- or hyperfunction of the pituitary gland,
• Hypo- or hyperfunction of the adrenal glands,
• Gender uncertainty,
• Ovarian and testicular dysfunction,
• Low blood sugar (hypoglycemia),
• Obesity,
• Vitamin D problems (rickets, hypocalcemia),
• Hyper- or hypocalcemia, juvenile osteoporosis,
• Diabetes mellitus, type 1 and type 2,
• Congenital adrenal hyperplasia,
• Turner Syndrome,
• Klinefelter’s Syndrome,
• Hypopituitarism,
• Adrenoleukodystrophy,
• Lipid Disorders,
• Multiple endocrine neoplasia,
• Polycystic ovary syndrome.

Main endocrine organs in children and their functions

The adrenal glands are located on top of the kidneys. They differ in structure: the right gland is triangular, and the left is in the shape of a crescent. Adrenal glands output:

• Corticosteroids are hormones involved in stress responses, regulating the immune system, and inflammation.
• Catecholamines, such as norepinephrine and adrenaline, released in response to stress.
• Aldosterone, which affects renal function.
• Androgens, or male sex hormones, including testosterone, which regulate the development of masculine traits such as facial hair growth and deeper voice.

The hypothalamus is located just above the brainstem and below the thalamus. This gland activates and controls the body’s involuntary functions, including breathing, heart rate, appetite, sleep, temperature, and circadian cycles, or daily rhythms.The hypothalamus connects the nervous system to the endocrine system through the attached pituitary gland.

Ovaries are located on either side of the uterus in girls. They secrete the hormones estrogen and progesterone. These hormones promote sexual development, fertility, and menstruation.

Testicles are located in the scrotum below the penis in boys. They secrete androgens, mainly testosterone. Androgens control sexual development, puberty, facial hair, sexual behavior, libido, erectile function, and sperm production.

The pancreas is located in the abdominal cavity and is both an endocrine gland and a digestive organ. She generates:

• insulin for the regulation of carbohydrate and fat metabolism in the body,
• somatostatin, which controls the functioning of the endocrine and nervous systems and controls the secretion of several hormones such as gastrin, insulin and growth hormone,
• glucagon – a peptide hormone that raises blood glucose levels when it falls too low,
• pancreatic polypeptide that regulates the secretion of substances produced by the pancreas.

Diabetes and digestive problems can occur with diseases of the pancreas.

The parathyroid glands are small endocrine glands located in the neck that produce the parathyroid hormone, which regulates the calcium and phosphate levels in the blood. Muscles and nerves can work efficiently only with a certain constant concentration of these substances in the blood.

The pineal gland is a small endocrine gland located deep in the brain.It releases melatonin and helps control sleep and reproductive hormone levels in the body.

The pituitary gland is an endocrine gland attached to the hypothalamus at the base of the brain. It is sometimes called the main endocrine gland because it secretes hormones that regulate the functions of other glands, as well as regulate growth and several other bodily functions. Anterior pituitary gland secretes hormones that affect sexual development, thyroid function, growth, skin pigmentation and adrenal function.If the anterior pituitary gland is insufficiently active, it can lead to stunted growth in childhood and insufficient activity in other endocrine glands.

The posterior pituitary gland secretes oxytocin, a hormone that enhances uterine contractions, and antidiuretic hormone (ADH), which regulates the reabsorption of fluid in the kidneys.

Thymus is an endocrine gland located under the sternum. T-lymphocytes (a type of immune cell) mature and multiply in the thymus in children.After puberty, the gland is resorbed. The thymus plays a role in building immunity in children.

The thyroid gland , located just below the Adam’s apple in the neck, produces hormones that play a key role in regulating blood pressure, body temperature, heart rate, metabolism, and how the body responds to other hormones. The thyroid gland uses iodine to produce hormones. The two main hormones it produces are thyroxine and triiodothyronine.It also produces calcitonin, which helps to strengthen bones and regulates calcium metabolism.

Diseases of the endocrine system in children

Disruption of hormones can be the result of congenital genetic defects or exposure to harmful environmental factors. Some babies are born with hormonal problems that can lead to a range of health problems such as short stature. Endocrine disrupting chemicals such as pesticides, lead and phthalates, which are used in plastic food containers, can also cause hormonal problems in children.

There are three broad groups of endocrine disorders:

1. The gland does not produce enough of its hormones. This is called hypofunction or hyposecretion of the endocrine glands.
2. The gland produces too many hormones – hyperfunction or hypersecretion of the gland.
3. Tumors of the endocrine glands. They can be malignant or benign.

In adrenal gland pathology , hypersecretion can lead to excessive nervousness, sweating, high blood pressure and Cushing’s disease.Hypofunction can lead to Addison’s disease, mineralocorticoid deficiency, weight loss, loss of energy, and anemia.

Hypersecretion of the pancreas can lead to hyperinsulinemia, and a decrease in blood glucose levels. Hyposecretion can lead to diabetes.

Hypersecretion of parathyroid glands can lead to fragility of bones and the formation of stones in the urinary system. Hyposecretion can lead to involuntary muscle contractions or tetany caused by low plasma calcium levels.

Hyperthyroidism is most commonly associated with Graves’ disease. This can lead to an accelerated metabolism, sweating, arrhythmias or irregular heartbeat, weight loss and nervousness in children. Hypothyroidism can lead to lethargy and fatigue, weight gain, depression, abnormal bone development, and stunted growth and development.

Hypersecretion of the pituitary gland can lead to gigantism or overgrowth, while hyposecretion can lead to slow bone growth and short stature.

Hypersecretion of thymus results in an overactive immune system that overreacts to perceived threats. This can lead to autoimmune disease. Hyposecretion can lead to a weakened immune system when the body is unable to fight infection and easily succumbs to viruses, bacteria, and other pathogens.

When should I make an appointment with a pediatric endocrinologist in St. Petersburg?

• A sharp change in the weight of the child.
• Excessive thirst, frequent trips to the toilet (signs of diabetes in children).
• Overweight, stretch marks and high blood pressure.
• Rapid fatigue, lethargy, drowsiness and restless sleep.
• Slight excitability, irritability and palpitations.
• Too early puberty (up to 8 years) with the manifestation of the corresponding signs (hair growth under the armpits and pubic hair, enlargement of the mammary glands, etc.).
• Big difference in height in relation to peers.
• Unusual body odor.

Preparing for a visit to the doctor

Because endocrine disorders can affect many aspects of a child’s growth and development, the doctor needs to gather as much information as possible about the child’s medical history. Parents can help by preparing all medical records and research findings from past years.

If the child is old enough to understand speech and events, he needs to explain the purpose of the visit to the doctor in terms that are understandable to him.The initial appointment will take from 1.5 to 2 hours. This will be enough for the doctor to take a history, conduct an examination, take the necessary tests and discuss the treatment plan with the parents. This will be a very long time for a child, therefore, in order for him to sit quietly, he needs to take toys or books with him.

What does the doctor do at the appointment?

During the appointment, the St. Petersburg pediatric endocrinologist examines the child and prescribes appropriate tests and studies.The most commonly used laboratory diagnostics and ultrasound. With the help of analyzes, the hormonal background is determined, and with the help of ultrasound, the endocrine glands are visually inspected. He will check the baby’s heart rate and blood pressure, and monitor the health of their skin, hair, teeth and mouth.

As a result of the examination, the doctor will make a conclusion and make a diagnosis, prescribe treatment, write out the necessary prescriptions and give recommendations. He will draw up a sheet of temporary disability, write out the necessary certificates for the child.

The treatment and follow-up plan will be discussed with the parents, who will have the opportunity to ask questions and leave with an understanding of your child’s condition and the doctor’s recommendations. Also, the endocrinologist will advise on the correct development of the child, the prevention of diseases, offer classes in physiotherapy exercises, aquatherapy and swimming, physiotherapy.

Analysis and research

The endocrinologist can carry out the following tests necessary to clarify the diagnosis:

• General and clinical blood tests.
• Urinalysis.
• Analysis of urine and blood for the content of hormones.
• Blood test for sugar (glucose) level.
• Biochemical blood test.
• Lipidogram – an assessment of the level of various types of cholesterol: high-density lipids, low-density lipids, triglyceride levels.
• Glycosylated hemoglobin.
• Test for glucose tolerance.
• Radiocompetitive microanalysis of hormones.
• Gamma-topographic surveys.
• Single-photon densitometry.
• Computed tomography.
• Magnetic resonance (nuclear magnetic) tomography.
• Phlebography.
• X-ray of the skull.
• Thyroid scintigraphy.
• Ultrasound examination.
• Fine-needle puncture biopsy of the thyroid gland (puncture of the thyroid gland).
• Thermography.
• Evaluation of bone density.

It is often necessary to measure blood hormone levels in order to make a complete assessment, and the tests usually take 1 to 2 weeks.Some tests must be done at specific times of the day and may need to be taken at home. Certain hormones must be measured under specific conditions. If necessary, you will have to schedule another visit specifically for testing.

Treatment of hormonal disorders and pathology of the endocrine glands

Hormonal growth disorders in children

Growth disorders are problems that prevent children from reaching normal height, weight, or puberty.Growth disorders may be associated with:

• The short stature of the parents, which means that the child can only achieve the same height.
• Stunting, also called constitutional stunting.
• Lack of hormones – for example, low levels of growth hormone, thyroid hormones, or pituitary hormones.
• A health condition that can cause poor growth, such as celiac disease, inflammatory bowel disease, or kidney disease.
• Genetic disorders such as Turner or Noonan syndromes.

Growth disorders in case of hormone deficiency, treated with hormone replacement therapy. In case of growth hormone deficiency, daily injections will be necessary.

Thyroid diseases

Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormones. Some babies are born with similar problems, while others develop autoimmune diseases, such as Hashimoto’s thyroiditis, which damage the thyroid gland.

Hyperthyroidism is a pathological condition when the thyroid gland produces too many hormones. Hyperthyroidism can be caused by Graves disease, hashitoxicosis, and overactive thyroid nodules.

Goiter (enlarged thyroid gland) – May indicate an insufficient or overactive thyroid gland. In some cases, the gland becomes so large that it causes trouble breathing or swallowing.

Thyroid nodules – e These are formations in the thyroid gland, which can often be benign, but rarely can be malignant.

Thyroid cancer – includes papillary, follicular and medullary thyroid cancer.

Genetic diseases may increase the risk of thyroid cancer in children. These include multiple endocrine neoplasia type 2 (MEN2), DICER1 syndrome, familial adenomatous polyposis (FAP), Gardner syndrome, Carney complex, Werner syndrome, and PTEN hamartoma tumor syndrome.

To diagnose diseases of the thyroid gland, the doctor palpates the organ and regional lymph nodes.Blood tests help to find out the level of production and hormonal imbalance. By checking the levels of certain hormones, including T4, T3, thyroid-stimulating hormone (TSH), and in some cases calcitonin, your doctor can determine if your thyroid is working properly. Blood tests can also detect thyroid antibodies, which are indicative of an autoimmune inflammatory process. Genetic testing can determine if there are genetic mutations that cause MEN2 or other conditions that increase a child’s risk of developing thyroid cancer.

For instrumental diagnostics, ultrasound of the thyroid gland is used, determining nodules in the structure of the gland, scanning the thyroid gland using radioactive iodine, and biopsy to detect cancer cells.

Methods for the treatment of thyroid diseases are selected taking into account the individual needs of the child and the nature of the disorders. The main goal of therapy is to restore hormone levels to normal in order to relieve symptoms and prevent complications.

In most cases, hypothyroidism can be safely and successfully treated with a daily dose of synthetic thyroid hormone.Hyperthyroidism can be treated with anti-thyroid medications, which stop the thyroid gland from producing hormones. Children with an overactive thyroid may also need to take beta blockers to lower heart rate, blood pressure, agitation, and tremors until thyroid hormone levels are under control.

In some cases, the child may be prescribed radioactive iodine preparations, which will destroy the thyroid gland.This is a permanent treatment option for children whose overactive thyroid cannot be treated with medication. In children with thyroid cancer, this treatment can be used after surgery to kill any remaining cancer cells. After the thyroid gland is destroyed, your child will take a daily dose of synthetic thyroid hormone, which will support normal growth, development, and long-term reproductive function.

Surgery can be used to remove part of the thyroid gland (lobectomy) or the entire gland (total thyroidectomy).This may be necessary to remove a large goiter, hyperactive nodules, or thyroid cancer. If all of the gland has been removed, your child will take a daily replacement dose of synthetic thyroid hormone.

Type 1 diabetes

Type 1 diabetes, also called juvenile diabetes, occurs when the body’s immune system destroys the cells in the pancreas that make insulin. Insulin is a hormone that takes sugar (known as glucose) from your bloodstream and delivers it to your cells for use as energy.Without insulin, blood sugar levels remain high, which can lead to serious complications over time. The diagnosis is made with blood and urine tests. Because children with type 1 diabetes do not produce insulin, patients should receive insulin in daily injections or using an insulin pump. They should also check their blood sugar levels throughout the day and pay particular attention to diet and exercise. Eating right to maintain healthy blood sugar levels and maintaining a healthy weight are critical to managing type 1 diabetes.Regular medical examinations and monitoring of blood sugar levels using urine and blood tests, including a blood test (A1C or glycated hemoglobin test), are mandatory. The pediatric endocrinologist will regularly assess the child’s kidney, thyroid and liver function, monitor blood pressure and physical growth. They will also refer the child to a pediatric optometrist for regular eye exams. These checks help prevent common diabetes complications such as vision problems.

Type 2 diabetes

In type 2 diabetes, the child’s body produces insulin, but either not enough or uses it ineffectively.This leads to high blood sugar levels, which can lead to serious complications over time. Type 2 diabetes is treated with metformin, which reduces the amount of sugar released by the liver into the bloodstream. Medication alone cannot control type 2 diabetes, so the child will have to diet, exercise, and control their weight all the time. Daily insulin injections may be needed to control daily blood sugar levels.

Sexual developmental disorders

Babies born with sexual development disorders (undifferentiated sex of the child) may have genitals that are clearly not male or female.It is the most common sexual development disorder in children.

It can occur due to chromosomal abnormalities, hormonal imbalances, including congenital adrenal hyperplasia.

Genital abnormalities include abnormal growth of the penis, scrotum or clitoris, impaired testicular development, and an absent or atypical vagina.

For the treatment of pathology, an operation to correct ambiguous or atypical genitals may be indicated. In addition to correcting physical problems that may affect a child’s health, surgery may be required to allow the child to have a normal sex life and the ability to have children in the future.The surgery is usually performed in boys between the ages of 6 and 18 months, when the growth of the penis is minimal. Girls can undergo surgery during this period of time, but vaginal surgeries that affect fertility may be delayed until puberty. Non-surgical techniques such as vaginal stretching can also be used.

For adolescents aged 16 and over, gender-appropriate hormone therapy can be used to induce physical and emotional changes that better match their gender identity.

Lipid metabolism disorders

Children may experience the following lipid disorders:

• High cholesterol or hypercholesterolemia (high blood cholesterol).
• High triglyceride levels or hypertriglyceridemia (high triglyceride levels in the blood).
• Lipid disorders associated with diabetes, obesity and metabolic syndrome (combination of high blood pressure, high blood sugar, unhealthy cholesterol and abdominal fat).

An endocrinologist will perform a physical examination and blood test to assess the child’s health. If blood tests show that the condition is the result of an inherited disorder, a geneticist will be brought in to determine if additional genetic testing is needed. If the disease affects the heart or kidneys, the pediatric endocrinologist will work closely with the pediatric cardiologist or nephrologist. Doctors will carefully assess the long-term risks of cardiovascular disease in a child and determine if medications may be helpful in treating lipid disorders.

Overweight children can have a range of health problems, from asthma and sleep apnea to diabetes, high blood pressure, liver problems, and joint pain. They are prone to social and emotional problems, some children may have low self-esteem, anxiety disorders and depression. These problems can accompany them into adulthood, putting them at risk of cardiovascular disease and other serious chronic diseases. Both being overweight and obese can increase the likelihood of developing serious complications.These problems include diabetes, high blood pressure, heart disease, stroke, gallstones, high cholesterol, gout, and many types of cancer. Obesity can even increase the risk of early death.

There is no one-size-fits-all approach to weight loss. Doctors always develop an individual method that suits the needs of the child. The nutrition and exercise plan takes into account your child’s history, complications that require treatment, and personal preferences and goals.

Some patients will require medication and a special diet under medical supervision.