HORMONES

#Hormones are chemical messengers produced by glands in the endocrine system. These messengers travel through the bloodstream to target cells or organs, where they exert specific effects on various physiological processes in the body.

🔵 Hormone levels are tightly regulated to maintain homeostasis in the body. Regulation occurs through various mechanisms, including feedback loops involving the endocrine glands, nervous system, and target organs.

🔵 Understanding hormones is essential for comprehending various aspects of human physiology and health, including the diagnosis and treatment of endocrine disorders.

🔵 Hormones can be classified into different categories based on their chemical structure:

◉ Steroid Hormones: These are derived from cholesterol and include hormones like estrogen, progesterone, and testosterone.

◉ Peptide Hormones: Made up of chains of amino acids, examples include insulin, growth hormone, and oxytocin.

◉ Amino Acid-Derived Hormones: Derived from amino acids such as tyrosine or tryptophan, examples include thyroid hormones and adrenaline.

🔵 Hormones play crucial roles in regulating numerous physiological processes:

◉ Metabolism: Controlling energy production, storage, and expenditure.

◉ Growth and Development: Regulating cell growth, differentiation, and development.

◉ Reproduction: Influencing reproductive processes such as menstruation, pregnancy, and sexual function.

◉ Stress Response: Managing the body's response to stress through the release of stress hormones like cortisol and adrenaline.

◉ Fluid and Electrolyte Balance: Maintaining proper levels of water and electrolytes in the body.

◉ Mood and Emotions: Impacting mood, emotions, and behavior through interactions with the nervous system.

◉ Immune Function: Modulating immune responses and inflammation.

🔵 Hormones are produced by specialized glands in the endocrine system:

◉ Pituitary Gland: Often referred to as the "master gland," it secretes hormones that regulate other endocrine glands.

◉ Thyroid Gland: Produces thyroid hormones that regulate metabolism.

◉ Adrenal Glands: Produce hormones such as cortisol, adrenaline, and aldosterone, involved in stress response and metabolism.

◉ Pancreas: Secretes insulin and glucagon, which regulate blood sugar levels.

◉ Gonads (Testes and Ovaries): Produce sex hormones like testosterone and estrogen.

1. INSULIN

◉ Produced by Pancreas (specifically, beta cells in the Islets of Langerhans)

◉ Regulates blood sugar levels by facilitating the uptake of glucose into cells for energy production and storage in the liver and muscles.

◉ Inhibits the breakdown of stored glycogen and fats.

2. GLUCAGON

◉ Produced by Pancreas (specifically, alpha cells in the Islets of Langerhans)

◉ Increases blood sugar levels by stimulating the liver to release stored glucose into the bloodstream.

◉ Promotes the breakdown of glycogen and the conversion of amino acids into glucose.

3. CORTISOL

◉ Produced by Adrenal glands (specifically, the adrenal cortex)

◉ Regulates metabolism by influencing glucose metabolism, protein metabolism and fat metabolism.

◉ Suppresses the immune system and reduces inflammation.

◉ Helps the body respond to stress by increasing blood sugar levels and enhancing the availability of energy sources.

4. ADRENALINE (EPINEPHRINE)

◉ Produced by Adrenal glands (specifically, the adrenal medulla)

◉ Initiates the body's fight-or-flight response by increasing heart rate, dilating airways, and mobilizing energy stores for quick use.

◉ Constricts blood vessels in the skin and gastrointestinal tract, redirecting blood flow to the muscles and brain.

5. NORADRENALINE (NOREPINEPHRINE)

◉ Produced by Adrenal glands (specifically, the adrenal medulla)

◉ Works alongside adrenaline to regulate blood pressure, heart rate, and the body's stress response.

◉ Constricts blood vessels, leading to increased blood pressure.

6. THYROXINE(T4)

◉ Produced by Thyroid gland

◉ Regulates metabolism by influencing the metabolic rate of cells throughout the body.

◉ Supports growth and development, particularly of the central nervous system in fetuses and infants.

7. TRIIODOTHYRONINE (T3)

◉ Produced by Thyroid gland

◉ Regulates metabolism, similar to thyroxine (T4), but more potent.

◉ Plays a crucial role in regulating body temperature, heart rate, and energy production.

8. GROWTH HORMONE (GH)

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Stimulates growth and development of bones, muscles, and organs.

◉ Regulates metabolism by promoting protein synthesis, fat metabolism, and glucose uptake in tissues.

9. PROLACTIN

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Stimulates milk production in the mammary glands following childbirth.

◉ Plays a role in regulating the immune system and behavior.

10. FOLLICLE-STIMULATINE HORMONE (FSH)

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Stimulates the growth and maturation of ovarian follicles in females, leading to ovulation.

◉ Stimulates spermatogenesis (sperm production) in males.

11. LUTEINIZING HORMONE (LH)

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Triggers ovulation and stimulates the production of estrogen and progesterone in females.

◉ Stimulates testosterone production in males, which is essential for sperm maturation and secondary sexual characteristics.

12. THYROID-STIMULATING HORMONE (TSH)

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Stimulates the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3), regulating metabolism and energy production.

◉ Promotes the growth and development of the thyroid gland.

13. ADRENOCORTICOTROPIC HORMONE (ACTH)

◉ Produced by Pituitary gland (specifically, the anterior pituitary)

◉ Stimulates the adrenal glands to produce cortisol and other corticosteroid hormones.

◉ Plays a role in the body's response to stress and inflammation.

14. MELATONIN

◉ Produced by Pineal gland

◉ Regulates sleep-wake cycles (circadian rhythms) and helps synchronize the body's internal clock with the external environment.

◉ Influences reproductive hormones and immune function.

15. ESTROGEN

◉ Produced by Ovaries (in females), testes and adrenal glands (in smaller amounts, in males)

◉ Regulates the menstrual cycle, promotes secondary sexual characteristics in females, and helps maintain bone density.

◉ Supports the growth and development of reproductive tissues and organs.

16. PROGESTERONE

◉ Produced by Ovaries (in females), testes and adrenal glands (in smaller amounts, in males)

◉ Prepares the uterus for pregnancy, maintains pregnancy, and regulates the menstrual cycle.

◉ Supports the growth and development of the placenta and fetus.

17. TESTOSTERONE

◉ Produced by Testes (in males), ovaries and adrenal glands (in smaller amounts, in females)

◉ Promotes the development of male secondary sexual characteristics, such as facial hair, deep voice, and muscle mass.

◉ Regulates sperm production, libido, and mood.

18. PARATHYROID HORMORE (PTH)

◉ Produced by Parathyroid glands

◉ Regulates calcium and phosphate levels in the blood by promoting bone resorption and increasing calcium absorption in the intestines and kidneys.

◉ Stimulates the production of calcitriol, the active form of vitamin D, which enhances calcium absorption.

19. CALCITONIN

◉ Produced by Thyroid gland (specifically, the parafollicular cells or C cells)

◉ Lowers blood calcium levels by inhibiting bone resorption and increasing calcium excretion by the kidneys.

◉ Inhibits the release of calcium from bone into the bloodstream.

20. ANTIDIURETIC HORMONE (ADH, Vasopressin)

◉ Produced by Hypothalamus (released by the posterior pituitary gland)

◉ Regulates water balance by promoting water reabsorption in the kidneys, reducing urine volume, and increasing blood pressure when necessary.

◉ Constricts blood vessels, raising blood pressure in cases of dehydration or low blood volume.

21. OXYTOCIN

◉ Produced by Hypothalamus (released by the posterior pituitary gland)

◉ Stimulates uterine contractions during childbirth and facilitates the progression of labor.

◉ Promotes milk ejection (letdown reflex) during breastfeeding.

◉ Plays a role in social bonding, trust, and emotional behavior.

22. ATRIAL NATIURETIC PEPTIDE (ANP)

◉ Produced by Heart (specifically, atrial cells)

◉ Regulates blood pressure and fluid balance by promoting sodium and water excretion by the kidneys, leading to decreased blood volume and blood pressure.

◉ Inhibits the release of renin and aldosterone, reducing blood vessel constriction and sodium retention.

23. GHRELIN ◉ Produced by Stomach and pancreas

◉ Stimulates appetite by acting on the hypothalamus to increase hunger and food intake.

◉ Regulates energy balance, growth hormone secretion, and gastrointestinal motility.

24. LEPTIN

◉ Produced by Adipose (fat) tissue

◉ Regulates appetite and energy expenditure by signaling satiety to the brain and influencing metabolism.

◉ Plays a role in maintaining body weight and fat stores by inhibiting hunger and promoting energy expenditure.

25. ADIPONECTIN

◉ Produced by Adipose (fat) tissue

◉ Regulates glucose metabolism and fatty acid oxidation, improving insulin sensitivity and reducing inflammation.

◉ Modulates lipid metabolism, vascular function, and immune response.

26. RENIN

◉ Produced by Kidneys

◉ Initiates the renin-angiotensin-aldosterone system (RAAS), leading to the production of angiotensin II, which helps regulate blood pressure and fluid balance.

◉ Stimulates vasoconstriction and aldosterone release, increasing blood pressure and sodium retention.

27. ALDOSTERONE

◉ Produced by Adrenal glands (specifically, the adrenal cortex)

◉ Regulates sodium and potassium levels in the blood by promoting sodium reabsorption and potassium excretion in the kidneys, thereby maintaining blood pressure and fluid balance.

◉ Stimulates water retention and blood volume expansion to maintain blood pressure.

28. ERYTHROPOIETIN

◉ Produced by Kidneys (and to a lesser extent, the liver)

◉ Stimulates the production of red blood cells (erythropoiesis) in the bone marrow in response to low oxygen levels in the blood.

◉ Maintains adequate tissue oxygenation and regulates hematocrit levels.

29. CORTICOTROPIN-RELEASING HORMONE (CRH)

◉ Produced by Hypothalamus

◉ Stimulates the anterior pituitary gland to release adrenocorticotropic hormone (ACTH), initiating the production and release of cortisol from the adrenal glands.

◉ Regulates the body's response to stress and maintains homeostasis.

30. GONADOTOPIN-RELEASING HORMONE (GnRH)

◉ Produced by Hypothalamus

◉ Stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland, which regulate reproductive function.

◉ Controls the menstrual cycle and ovulation in females, and regulates sperm production and testosterone secretion in males.

31. INSULINE-LIKE GROWTH FACTOR 1 (IGF-1)

◉ Produced by Liver (and other tissues in response to growth hormone stimulation)

◉ Mediates the growth-promoting effects of growth hormone (GH) on bones, muscles, and other tissues during childhood and adolescence.

◉ Regulates cell growth, differentiation, and metabolism throughout life.

32. RELAXIN

◉ Produced by Ovaries (in females), placenta, and other tissues

◉ Facilitates cervical dilation and softening of the pubic symphysis during childbirth.

◉ Inhibits uterine contractions early in pregnancy, promoting implantation and fetal development.

33. SOMATOSTATIN

◉ Produced by Hypothalamus, pancreas, and other tissues

◉ Inhibits the release of growth hormone (GH), insulin, glucagon, and other hormones, regulating their secretion and actions.

◉ Modulates gastrointestinal motility, neurotransmission, and cell proliferation.

34. SUBSTANCE P (SP)

◉ Produced by Nervous system (neurons and immune cells)

◉ Acts as a neurotransmitter and neuromodulator in the central and peripheral nervous systems, transmitting pain signals and regulating pain perception.

◉ Modulates inflammation, immune response, and neurogenic inflammation.

35. THYMOSIN

◉ Produced by Thymus gland

◉ Regulates the maturation and function of T lymphocytes (T cells) involved in the immune response, particularly during early life and in response to infection.

◉ Supports the development of immune tolerance and prevents autoimmunity.

36. SECRETIN

◉ Produced by Small intestine (duodenum)

◉ Stimulates the pancreas to release bicarbonate-rich pancreatic juice, neutralizing acidic chyme from the stomach and facilitating digestion in the small intestine.

◉ Inhibits gastric acid secretion and motility, slowing the emptying of the stomach to allow for efficient digestion and nutrient absorption.

37. GASTRIN

◉ Produced by Stomach (G cells in the gastric mucosa)

◉ Stimulates gastric acid secretion by parietal cells in the stomach, promoting digestion and killing ingested pathogens.

◉ Stimulates gastric motility and emptying, facilitating the movement of food through the digestive tract.

38. CHOLECYSTOKININ (CCK)

◉ Produced by Small intestine (duodenum and jejunum)

◉ Stimulates the gallbladder to contract and release bile into the small intestine, aiding in the digestion and absorption of fats.

◉ Inhibits gastric emptying and appetite, promoting feelings of fullness and satiety.

39. Motilin

◉ Produced by Small intestine (duodenum and jejunum)

◉ Stimulates gastric and intestinal motility, particularly during fasting and between meals, to facilitate the movement of food through the digestive tract.

◉ Coordinates the migrating motor complex, a cyclical pattern of gastrointestinal motility that occurs during fasting periods.