HARMONES and their functions

HARMONES and their functions

Hormones are chemical messengers produced by various glands in the body that help regulate and coordinate the activities of different cells, tissues, and organs. They play a crucial role in maintaining overall homeostasis and controlling various physiological processes.

Here are some important hormones and their functions:

▪️Insulin: Produced by the pancreas, insulin regulates the metabolism of carbohydrates, fats, and proteins. It helps lower blood glucose levels by facilitating the uptake of glucose into cells.

▪️Glucagon: Also produced by the pancreas, glucagon works in opposition to insulin. It raises blood glucose levels by stimulating the breakdown of glycogen into glucose in the liver, a process called glycogenolysis.

▪️Thyroid hormones (T3 and T4): Produced by the thyroid gland, these hormones regulate metabolism, growth, and development in the body. They influence the functioning of various organs and tissues, including the heart, brain, and muscles.

▪️Adrenaline (epinephrine) and Noradrenaline (norepinephrine): These hormones are released by the adrenal glands and are involved in the body's response to stress. They increase heart rate, blood pressure, and blood glucose levels, preparing the body for a "fight or flight" response.

▪️Cortisol: Also produced by the adrenal glands, cortisol plays a role in the body's response to stress. It helps regulate metabolism, reduce inflammation, and maintain blood pressure.

▪️Growth hormone: Produced by the pituitary gland, growth hormone stimulates growth and development in children and adolescents. It also plays a role in regulating metabolism and maintaining healthy body composition in adults.

▪️Estrogen and progesterone: These female sex hormones are primarily produced by the ovaries. They regulate the menstrual cycle, promote the development of female reproductive organs, and play a role in pregnancy and lactation.

▪️Testosterone: The primary male sex hormone, testosterone, is produced by the testes. It is responsible for the development of male reproductive organs, secondary sexual characteristics, and plays a role in muscle growth and bone density.

▪️Melatonin: Produced by the pineal gland, melatonin regulates the sleep-wake cycle and helps maintain the body's internal clock. It is released in response to darkness and promotes sleep.

▪️Leptin: Produced by fat cells, leptin helps regulate appetite and body weight. It signals the brain to reduce hunger and increase energy expenditure.

▪️Parathyroid hormone (PTH): Produced by the parathyroid glands, PTH regulates calcium and phosphate levels in the blood. It increases calcium release from bones, enhances calcium absorption in the intestines, and promotes calcium reabsorption in the kidneys.

▪️Calcitonin: Produced by the thyroid gland, calcitonin plays a role in regulating calcium levels in the blood. It inhibits the release of calcium from bones, promoting its deposition in bones and reducing blood calcium levels.

▪️Aldosterone: Produced by the adrenal glands, aldosterone regulates sodium and potassium balance in the body. It acts on the kidneys, promoting sodium reabsorption and potassium excretion, thus helping to maintain blood pressure and fluid balance.

▪️Oxytocin: Produced by the hypothalamus and released by the pituitary gland, oxytocin is often referred to as the "love hormone." It plays a role in social bonding, trust, and maternal-infant attachment. It also stimulates uterine contractions during childbirth and promotes milk ejection during breastfeeding.

▪️Follicle-stimulating hormone (FSH) and luteinizing hormone (LH): Produced by the pituitary gland, FSH and LH are involved in the regulation of the reproductive system. FSH stimulates the growth of ovarian follicles in females and sperm production in males. LH triggers ovulation in females and stimulates testosterone production in males.

▪️Melanocyte-stimulating hormone (MSH): Produced by the pituitary gland, MSH plays a role in regulating skin pigmentation. It stimulates the production and dispersion of melanin, the pigment responsible for skin, hair, and eye color.

▪️Ghrelin: Produced by the stomach, ghrelin is often referred to as the "hunger hormone." It stimulates appetite, increases food intake, and promotes fat storage. Ghrelin levels increase before meals and decrease after eating.

▪️Leptin: Produced by fat cells, leptin plays a role in regulating appetite and energy balance. It acts on the hypothalamus to reduce hunger and increase energy expenditure. Leptin levels are higher in individuals with more fat mass.

▪️Prostaglandins: Prostaglandins are not hormones per se, but they are hormone-like substances that are produced in various tissues throughout the body. They play a role in inflammation, pain, blood clotting, and reproductive functions such as inducing uterine contractions during menstruation and labor.

▪️Prolactin: Produced by the pituitary gland, prolactin is involved in milk production and lactation in females. It stimulates breast development during pregnancy and initiates milk production after childbirth.

▪️Thyroid-stimulating hormone (TSH): Also produced by the pituitary gland, TSH regulates the production and release of thyroid hormones (T3 and T4) from the thyroid gland. It plays a crucial role in maintaining thyroid function and metabolism.

▪️Antidiuretic hormone (ADH) or Vasopressin: Produced by the hypothalamus and released by the pituitary gland, ADH helps regulate water balance in the body. It acts on the kidneys, promoting water reabsorption and reducing urine output.

▪️Relaxin: Produced by the ovaries during pregnancy and by the placenta, relaxin helps relax and soften the ligaments and tissues in the pelvis. It facilitates childbirth by allowing the pelvis to expand and aids in the implantation of the fertilized egg in the uterus.

▪️Thymosin: Produced by the thymus gland, thymosin plays a role in the development and maturation of T-lymphocytes, which are critical for the immune system's functioning. It helps support the production of immune cells and their response to pathogens.

▪️Atrial natriuretic peptide (ANP): Produced by the heart's atrial cells, ANP helps regulate blood pressure and fluid balance. It promotes the excretion of sodium and water by the kidneys, thereby reducing blood volume and blood pressure.

▪️Erythropoietin (EPO): Produced mainly by the kidneys, EPO stimulates the production of red blood cells in the bone marrow. It helps maintain adequate oxygen-carrying capacity in the blood.

▪️Cholecystokinin (CCK): Produced in the small intestine, CCK plays a role in digestion. It stimulates the release of bile from the gallbladder and pancreatic enzymes, which aid in the breakdown of fats and proteins.

▪️Inhibin: Produced by the gonads (ovaries in females, testes in males), inhibin regulates the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. It helps modulate the menstrual cycle in females and regulate sperm production in males.

▪️Parathyroid Hormone-related Protein (PTHrP): PTHrP is produced by various tissues in the body and shares similarities with parathyroid hormone. It plays a role in regulating calcium and phosphate levels, bone development, and tooth eruption.

▪️Gastrin: Gastrin is produced by the stomach and stimulates the production of gastric acid, which aids in digestion. It also promotes the contraction of stomach muscles and increases blood flow to the stomach.

▪️Secretin: Secretin is produced by the small intestine in response to acidic chyme (partially digested food) entering the duodenum. It stimulates the pancreas to release bicarbonate, which helps neutralize stomach acid, and it also promotes the release of bile from the gallbladder.

▪️Cholecystokinin (CCK): In addition to its role in digestion mentioned earlier, CCK also acts as a satiety hormone. It is released in response to food intake and helps regulate appetite by signaling feelings of fullness.

▪️Corticotropin-releasing hormone (CRH): Produced by the hypothalamus, CRH stimulates the release of adrenocorticotropic hormone (ACTH) from the pituitary gland. ACTH, in turn, stimulates the release of cortisol from the adrenal glands, helping the body respond to stress.

▪️Erythropoietin (EPO): Besides its role in red blood cell production mentioned earlier, EPO also plays a role in promoting blood vessel growth and repair, particularly in response to tissue injury or oxygen deprivation.

▪️Natriuretic Peptides: Natriuretic peptides, such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), are released by the heart in response to increased blood volume and pressure. They help regulate fluid balance by promoting the excretion of sodium and water by the kidneys, thus reducing blood volume and blood pressure.

▪️Inhibin and Activin: In addition to their role in regulating FSH production, inhibin and activin are involved in the feedback control of reproductive hormones. Inhibin helps inhibit the release of FSH, while activin promotes its release.

▪️Adiponectin: Adiponectin is a hormone secreted by adipose tissue (fat cells). It plays a role in regulating glucose and lipid metabolism and has anti-inflammatory effects. Low levels of adiponectin are associated with insulin resistance and metabolic disorders.

▪️Renin: Renin is an enzyme released by specialized cells in the kidneys in response to low blood pressure or low blood volume. It initiates the renin-angiotensin-aldosterone system (RAAS) by converting angiotensinogen into angiotensin I, leading to increased blood pressure and the release of aldosterone.

▪️Aldosterone: In addition to its role in regulating sodium and potassium balance mentioned earlier, aldosterone promotes the reabsorption of water in the kidneys, helping to regulate blood volume and blood pressure.

▪️Osteocalcin: Osteocalcin is a hormone produced by bone-forming cells called osteoblasts. It plays a role in bone remodeling and mineralization. Osteocalcin also influences glucose metabolism and insulin sensitivity.

▪️Fibroblast Growth Factor 23 (FGF23): FGF23 is produced by osteocytes in bone tissue and plays a role in regulating phosphate and vitamin D metabolism. It helps maintain phosphate balance by reducing its absorption in the intestines and promoting its excretion by the kidneys.

▪️Relaxin: In addition to its role during pregnancy, relaxin also plays a role in female reproductive health outside of pregnancy. It helps prepare the uterus for implantation, facilitates sperm transport, and may have anti-inflammatory effects.

▪️Thrombopoietin: Thrombopoietin is a hormone produced by the liver and kidneys that regulates the production of platelets in the bone marrow. It stimulates the differentiation and maturation of megakaryocytes, which are the cells that give rise to platelets.

▪️Gastric Inhibitory Peptide (GIP): GIP is produced by the small intestine in response to the ingestion of food, particularly carbohydrates and fats. It stimulates the release of insulin from the pancreas and inhibits gastric acid secretion, helping to regulate blood sugar levels.

▪️Vasopressin (ADH): In addition to its role in regulating water balance, ADH also acts as a vasoconstrictor, helping to constrict blood vessels and regulate blood pressure.

▪️PYY (Peptide YY): PYY is released by cells in the gastrointestinal tract, particularly in response to food intake. It helps regulate appetite by signaling feelings of fullness and satiety.