Endocrine System Physiology PDF

ENDOCRINE SYSTEM PHYSIOLOGY Thyroid Gland and Its Hormones Adrenal cortex hormones Gonads and Its Hormones THYROI D G L A N D H O R M O N E S It is the largest endocrine gland in the body. The thyroid gland is a shield-shaped gland...

ENDOCRINE SYSTEM PHYSIOLOGY Thyroid Gland and Its Hormones Adrenal cortex hormones Gonads and Its Hormones THYROI D G L A N D H O R M O N E S It is the largest endocrine gland in the body. The thyroid gland is a shield-shaped gland located in the lower anterior region of the neck, in the lower part of the larynx and above the trachea, at the level of the 5th neck and 1st thoracic vertebrae.I  it weighs about 25-30 grams. This gland consists of two lobes, right and left. The part connecting these lobes in front is called isthmus part. Isthmus part is in front of the 2nd, 3rd and 4th tracheal rings. The thyroid gland, which is rich in veins, is brown red in color. THYROID G L A N D H O R M O N ES TSH stimulates the regulation of thyroid hormones. T3 (Tri-iodothyronine) T4 (Thyroxine) CT (Calsitonin) T3 T4  The functions of thyroid gland hormones Provides normal growth and development by providing protein synthesis. It regulates the metabolic activities in the body. Due to the acceleration of oxidation, the consumption of oxygen and the production of carbon dioxide increase.  It regulates body temperature. It increases the respiratory rate. It provides normal growth and development by providing its synthesis. Increases the oxidation of fatty acids and fatty acids in the cells from the adipose tissue T3 (Tri-iodothyronine): It is very active. Little swing. T4 (Thyroxine): Less active. Releases abundantly. It becomes active by turning to T3 in plasma. T3 and T4..... It stimulates tissue metabolism. Increases sympathetic activity. Makes the heart work fast Thyroxine hormone converts glycogen into glucose from the liver and prevents the formation of glycogen. It provides physical and mental development in children. Thyroxine facilitates the kidney function and increases the amount of urine. Calcitonin (thyrocalcitonin) hormone is secreted from the thyroid gland follicles when the calcium level in the blood increases. It regulates the calcium level in the blood by showing a lowering effect. Calcitonin accelerates the storage of excess calcium in the bones in order to reduce the calcium level in the blood to normal.  Thus, the calcium level in the blood returns to normal. It also prevents the reabsorption of calcium from the kidneys and speeds up the urinary excretion of calcium. It continues until the calcium level in the blood returns to normal. In order for the thyroid gland to synthesis thyroxine hormone, iodine must be taken with foods. In order to make a normal amount of hormones, the body needs 1 mg of iodine per week. The body cannot synthesize iodine. Iodine, which is absorbed with food, passes into the blood, is held by the thyroid tissue sacs. The TSH hormone stimulates this effect. Iodine turns into free iodine by cell enzymes and enters the colloid substance in the vesicles and binds to tyrosine molecules there. Mono and di iodo derivatives occur. These, in turn, form the hormones triiodothyronine (T3) and tetraiodothyronine (T4- thyroxine). These are iodized thyroid hormones. T3 and T4 hormones pass into the blood and are transported by binding to blood proteins.  Thyroid secretion decreases as a result of insufficient functioning of the thyroid gland for any reason, this condition is called hypothyroidism. Failure or less secretion of thyroid hormones in the newborn and childhood period causes the emergence of the picture called cretinism.  Physical and mental retardation (dwarfism and mental retardation) are seen together in cretinism. Thyroid insufficiency seen in adults is called mixed edema. In case of mixed edema, tiredness, dryness of skin and hair and swelling of the face occur.  Hyperthyroidism is when thyroid hormones are secreted more than normal. This is called thyrotoxicosis (Basedow- graves disease). The amount of TSH increases, the thyroid gland works and grows continuously, depending on the constant stimulation of TSH to the thyroid gland.  The enlargement of the thyroid gland due to hypo or hyperthyroidism is called goiter.  In hyperthyroism, TSH is inhibited (suppressed) due to the increase of thyroid hormones. However, if the feed-beck mechanism does not work and the thyroid hormone continues to be excessively secreted, the thyroid gland grows. CT (Calsitonin): Prevents bone resorption Prevents osteoporosis PA R AT H Y R O I D H O R M O N E S PA R AT H Y RO ID G L A N D H O R M O N E S It is 4 glands located around the thyroid. Parathormone: It stimulates bone resorption. Increases plasma Ca ++ level. Hypocalcemia occurs in PTH deficiency. Cramps up to tetania develop. Itis usually a complication of thyroid surgery. PA N C R EA S G L A ND HOR MONES Insulin: Released from Langerhans islets. It stimulates glucose storage in the liver. It enables glucose to be used by cells. It decreases blood sugar. DiabetesMellitus in results from its Deficiency  As a result of insufficient secretion of insulin, glucose cannot be stored in the liver as glycogen and cannot be used sufficiently by the cells. As a result, the level of glucose in the blood rises. Ifthe glucose level in the blood is above normal due to insufficient secretion of insulin for any reason, it is called hyperglycemia. The accumulation of glucose in the blood causes diabetes mellitus.  Ifthe glucose level in the blood falls below normal due to the secretion of insulin above normal, it is called hypoglycemia. In this case, the brain is most affected. Because the brain's only energy source is glucose. Hypoglycemic shock and death develop in the later stages of hypoglycemia. Glucagon: Increases glucose release from the liver. It increases blood sugar.  Adrenal glands (gl. Suprenalis) are two yellowish glands located above both kidneys. İstinye Üniversitesi Uzaktan Eğitim Merkezi Each one weighs an average of 6– 7 grams. The adrenal glands consist of two parts, internal and external. Itsinner part is called the adrenal medulla (core), and its outer part is called the adrenal cortex (shell). Differenthormones in terms of structure and function are secreted from both parts.  It has two parts called the C ortex and Medulla. Steroid hormones are released from the cortex (Mineralocorticoids, Glucocorticoids, Adrenocortical, androgens), Adrenaline and noradrenaline are released from the medulla. ADRENAL CORTEX HORMONES: Steroid hormones are synthesized from the adrenal cortex, so these hormones are also called corticosteroid hormones. Most important ones; glucocorticoids, mineralocorticoids and androcorticoids. Hormones differ from each other in their functions. 1. Glucocorticoids It is mostly effective on protein, fat and carbohydrate metabolism. The most important hormones in this group are cortisol and corticosterone (cortisone and hydrocortisone).  Functions of glucocorticoids By affecting the liver, it provides the formation of glucose from proteins and fats and the storage of glucose in the liver. It reduces the use of glucose in cells. Thus, the amount of glucose in the blood increases.  It increases the breakdown of proteins and decreases protein synthesis. It reduces protein stores in muscle tissue other than the liver. It increases the breakdown of fats, free fatty acid ratio and usage. As well as the metabolic effects of glucocorticoids, the symptoms of inflammation and has allergy- relieving effects. Disorders seen in the absence of cortisone Blood glucose level decreases. Deficiencies occur in the formation of free fatty acids from the adipose tissue. Blood pressure drops. Reduces the permeability of the distal tubule to water, causing more water to be thrown away.  When excessive water is drunk in cortisol deficiency, it causes water accumulation in the body and water poisoning. Taste perception, hearing and smell deficiencies can be seen. Muscle weakness is seen. Although the cause is not known exactly, thethymus gland and lymph nodes enlarge in its absence.  Mineralocorticoids The most important hormones in this group are aldesteron and desoxycorticosterone. Aldesteron is a necessary hormone to maintain fluid and electrolyte balance in the body. It shows its main effect on sodium.  Aldesterone acts on the nephron tubules of the kidneys, allowing sodium to be reabsorbed from the kidneys, and accelerating the urinary excretion of potassium and hydrogen ions from the kidneys. Increasing the amount of sodium causes an increase in osmotic pressure and the absorption of water at the same rate. Thus, the water and electrolyte balance in body fluids is provided. In addition, aldosterone supports the defense system against infections.  Dezoxycorticosterone increases the connective tissue in inflammation, thus repairing the tissue. The reabsorption of sodium, water and chloride decreases in case of insufficient secretion of aldesteron.  Blood volume and heart rate slows down, and circulatory shock develops as a result. In the excess of aldosterone, the amount of potassium decreases due to the excess potassium excretion from the body and muscle weakness is seen.  Adrenocortical androgens Sexual hormones secreted from the cortex are progesterone, estrogen and androgen. Androgen plays a role in the increase of voice thickening, hair growth and muscle tone in men. It is effective in the emergence of the gender instinct in women. The secretion of androcorticoids is under the control of ACTH. These hormones are also produced in testicular cells.  ADRENAL MEDULLA HORMONES Two hormones, adrenaline (epinephrine) and noradrenaline (norepinephrine), are secreted from the adrenal medulla with sympathetic stimulation. 80% of the hormones secreted from this section are adrenaline and 20% is noradrenaline.  Adrenal medulla hormones are also called catecholamines. Adrenaline and noradrenaline have the same effects on some organs and different effects on others. The release of these hormones increases in situations of fear, excitement, rage, and stress. Effects of adrenaline and noradrenaline It increases blood pressure by accelerating the work of the heart. It constricts the superficial, peripheral blood vessels. Skeletal muscles expand blood vessels.  It increases the sugar level in the blood by affecting the conversion of glycogen in the liver to glucose. Increases oxygen consumption. It causes a slowdown in the digestive tract. It allows the pupils (pupils) to expand. Noradrenaline constricts capillaries, increases blood pressure.  PLACENTA HORMONES It is the bed that nourishes and protects the fetus. Progesterone: It protects pregnancy.... It plays a role in uterus and breast development. Estrodiol: It is thought to help progesterone. HCG (human chorionic gonadotropin): Protects pregnancy. HPL (human placenta lactogen): PRL-like effect.... Stimulates bone and muscle growth.... Increases protein synthesis  METABOLIC AND ENDOCRINE FUNCTIONS OF THE LUNGS Surfactant: Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by epithelial type II cells. The main function of surfactant is to lower the surface tension at the air/liquid interface within the alveoli of the lung.  Prostaglandin: The prostaglandins are a group of lipids made at sites of tissue damage or infection that are involved in dealing with injury and illness. Evidence exists implicating prostaglandins as mediators of asthma and of chronic inflammation in the lung.  Histamine: increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engalf pathogens in infections. Angiotensin Converting enzyme (ACE) ***Angiotensin-converting enzyme (ACE) inhibitors help relax your veins and arteries to lower your blood pressure. ACE inhibitors prevent an enzyme in your body from producing angiotensin II, a substance that narrows your blood vessels. This narrowing can cause high blood pressure and force your heart to work harder. ENDOCRINE FUNCTION OF KIDNEY Severe decrease in systemic blood pressure Decreased blood pressure to the glomeruli Decrease in the amount of blood coming to the kidney Sympathetic system stimulation Decrease in the amount of sodium in the body Secreting renin from kidneys  In addition, kidneys synthesize PgE2, PgF2 and erythropoietin required for erythropoiesis besides renin. THANK YOU