The endocrine system is a system of small organs that involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, growth, development and puberty, and tissue function and also plays a part in determining mood.[1] The field of study that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine. Major endocrine glands. (Male on the left, female on the right.) 1. Pineal gland 2. Pituitary gland 3. Thyroid gland 4. Thymus 5. Adrenal gland 6. Pancreas 7. Ovary 8. Testes Function The endocrine system is an information signal system much like the nervous system. However, the nervous system uses nerves to conduct information, whereas the endocrine system mainly uses blood vessels as information channels. Glands located in many regions of the body release into the bloodstream specific chemical messengers called hormones. Hormones regulate the many and varied functions of an organism, e.g., mood, growth and development, tissue function, and metabolism, as well as sending messages and acting on them. Types of signaling The typical mode of cell signaling in the endocrine system is endocrine signaling. However, there are also other modes, i.e., paracrine, autocrine, and neuroendocrine signaling.[2] Purely neurocrine signaling between neurons, on the other hand, belongs completely to the nervous system. Endocrine A number of glands that signal each other in sequence is usually referred to as an axis, for example, the hypothalamic-pituitary-adrenal axis. Typical endocrine glands are the pituitary, thyroid, and adrenal glands. Features of endocrine glands are, in general, their ductless nature, their vascularity, and usually the presence of intracellular vacuoles or granules storing their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen. Autocrine Other signaling can target the same cell. Paracrine Paracrine signaling is where the target cell is nearby. Juxtacrine Juxtacrine signals are transmitted along cell membranes via protein or lipid components integral to the membrane and are capable of affecting either the emitting cell or cells immediately adjacent. Role in disease Diseases of the endocrine system are common,[3] including conditions such as diabetes mellitus, thyroid disease, and obesity. Endocrine disease is characterized by dysregulated hormone release (a productive pituitary adenoma), inappropriate response to signaling (hypothyroidism), lack or destruction of a gland (diabetes mellitus type 1, diminished erythropoiesis in chronic renal failure), or structural enlargement in a critical site such as the neck (toxic multinodular goitre). Hypofunction of endocrine glands can occur as a result of loss of reserve, hyposecretion, agenesis, atrophy, or active destruction. Hyperfunction can occur as a result of hypersecretion, loss of suppression, hyperplastic or neoplastic change, or hyperstimulation. Endocrinopathies are classified as primary, secondary, or tertiary. Primary endocrine disease inhibits the action of downstream glands. Tertiary endocrine disease is associated with dysfunction of the hypothalamus and its releasing hormones. Cancer can occur in endocrine glands, such as the thyroid, and hormones have been implicated in signaling distant tissues to proliferate, for example, the estrogen receptor has been shown to be involved in certain breast cancers. Endocrine, paracrine, and autocrine signaling have all been implicated in proliferation, one of the required steps of oncogenesis.[4] Table of endocrine glands and secreted hormones Hypothalamus Secreted hormone | Abbreviation | From cells | Effect Thyrotropin-releasing hormone | TRH | Parvocellular neurosecretory neurons | Release thyroid-stimulating hormone from anterior pituitary (primarily) Stimulate prolactin release from anterior pituitary. Gonadotropin-releasing hormone | GnRH | Neuroendocine cells of the Preoptic area | Release of FSH and LH from anterior pituitary. Growth hormone-releasing hormone | GHRH | Neuroendocrine neurons of the Arcuate nucleus | Release GH from anterior pituitary Corticotropin-releasing hormone | CRH | Parvocellular neurosecretory neurons | Release ACTH from anterior pituitary Oxytocin | Magnocellular neurosecretory cells | Contraction of cervix and vagina Involved in orgasm, trust between people.[5] and circadian homeostasis (body temperature, activity level, wakefulness).[6] release breast milk Vasopressin | ADH or AVP | Parvocellular neurosecretory neurons | Increases permeability of distal convoluted tubule and collecting duct to water in the nephrons of the kidney, thus increasing water reabsorbtion. Somatostatin, also growth hormone-inhibiting hormone | SS or GHIH | Neuroendocrine cells of the Periventricular nucleus | Inhibit release of GH and TSH from anterior pituitary Prolactin inhibiting hormone or Dopamine | PIH or DA | Dopamine neurons of the arcuate nucleus | Inhibit release of prolactin and TSH from anterior pituitary Prolactin-releasing hormone | PRH | Release prolactin from anterior pituitary Pineal body (epiphysis) Secreted hormone | From cells | Effect Melatonin (Primarily) | Pinealocytes | antioxidant and causes drowsiness Pituitary gland (hypophysis) Anterior pituitary lobe (adenohypophysis) Secreted hormone | Abbreviation | From cells | Effect Growth hormone | GH | Somatotropes | stimulates growth and cell reproduction Release Insulin-like growth factor 1 from liver Prolactin | PRL | Lactotropes | milk production in mammary glands sexual gratification after sexual acts Adrenocorticotropic hormone or corticotropin | ACTH | Corticotropes | synthesis of corticosteroids (glucocorticoids and androgens) in adrenocortical cells Lipotropin | Corticotropes | lipolysis and steroidogenesis, stimulates melanocytes to produce melanin Thyroid-stimulating hormone or thyrotropin | TSH | Thyrotropes | stimulates thyroid gland to secrete thyroxine (T4) and triiodothyronine (T3) Follicle-stimulating hormone | FSH | Gonadotropes | In female: stimulates maturation of Graafian follicles in ovary. In male: spermatogenesis, enhances production of androgen-binding protein by the Sertoli cells of the testes Luteinizing hormone | LH | Gonadotropes | In female: ovulation In male: stimulates Leydig cell production of testosterone Posterior pituitary lobe (neurohypophysis) f ing Secreted hormone | Abbreviation | From cells | Effect Oxytocin | Magnocellular neurosecretory cells | Contraction of cervix and vagina Involved in orgasm, trust between people.[5] and circadian homeostasis (body temperature, activity level, wakefulness).[6] release breast milk Vasopressin or antidiuretic hormone | AVP or ADH | Magnocellular neurosecretory cells | retention of water in kidneys moderate vasoconstriction Oxytocin and anti-diuretic hormone are not secreted in the posterior lobe, merely stored. Intermediate pituitary lobe (pars intermedia) Secreted hormone | Abbreviation | From cells | Effect Melanocyte-stimulating hormone | MSH | Melanotroph | melanogenesis by melanocytes in skin and hair. Thyroid Secreted hormone | Abbreviation | From cells | Effect Triiodothyronine | T3 | Thyroid epithelial cell | potent form of thyroid hormone: increase the basal metabolic rate & sensitivity to catecholamines, affect protein synthesis Thyroxine or tetraiodothyronine | T4 | Thyroid epithelial cells | less active form of thyroid hormone: increase the basal metabolic rate & sensitivity to catecholamines, affect protein synthesis, often functions as a prohormone Calcitonin | Parafollicular cells | Construct bone reduce blood Ca2+ Parathyroid Secreted hormone | Abbreviation | From cells | Effect Parathyroid hormone | PTH | Parathyroid chief cell | increase blood Ca2+: *indirectly stimulate osteoclasts Ca2+ reabsorption in kidney activate vitamin D (Slightly) decrease blood phosphate: decreased reuptake in kidney but increased uptake from bones activate vitamin D Heart Secreted hormone | Abbreviation | From cells | Effect Atrial-natriuretic peptide | ANP | Cardiac myocytes | Reduce blood pressure by: reducing systemic vascular resistance, reducing blood water, sodium and fats Brain natriuretic peptide | BNP | Cardiac myocytes | (To a lesser degree than ANP) reduce blood pressure by: reducing systemic vascular resistance, reducing blood water, sodium and fats Striated muscle Secreted hormone | From cells | Effect Thrombopoietin | Myocytes | stimulates megakaryocytes to produce platelets[7] Skin Secreted hormone | From cells | Effect Calcidiol (25-hydroxyvitamin D3) | Inactive form of Vitamin D3 Adipose tissue Secreted hormone | From cells | Effect Leptin (Primarily) | Adipocytes | decrease of appetite and increase of metabolism. Estrogens[8] (mainly Estrone) | Adipocytes Stomach Secreted hormone | Abbreviation | From cells | Effect Gastrin (Primarily) | G cells | Secretion of gastric acid by parietal cells Ghrelin | P/D1 cells | Stimulate appetite, secretion of growth hormone from anterior pituitary gland Neuropeptide Y | NPY | increased food intake and decreased physical activity Secretin | S cells | Secretion of bicarbonate from liver, pancreas and duodenal Brunner's glands Enhances effects of cholecystokinin Stops production of gastric juice Somatostatin | D cells | Suppress release of gastrin, cholecystokinin (CCK), secretin, motilin, vasoactive intestinal peptide (VIP), gastric inhibitory polypeptide (GIP), enteroglucagon Lowers rate of gastric emptying Reduces smooth muscle contractions and blood flow within the intestine.[9] Histamine | ECL cells | stimulate gastric acid secretion Endothelin | X cells | Smooth muscle contraction of stomach[10] Duodenum Secreted hormone | From cells | Effect Cholecystokinin | I cells | Release of digestive enzymes from pancreas Release of bile from gallbladder hunger suppressant Liver Secreted hormone | Abbreviation | From cells | Effect Insulin-like growth factor (or somatomedin) (Primarily) | IGF | Hepatocytes | insulin-like effects regulate cell growth and development Angiotensinogen and angiotensin | Hepatocytes | vasoconstriction release of aldosterone from adrenal cortex dipsogen. Thrombopoietin | Hepatocytes | stimulates megakaryocytes to produce platelets[7] Pancreas Secreted hormone | From cells | Effect Insulin (Primarily) | Я Islet cells | Intake of glucose, glycogenesis and glycolysis in liver and muscle from blood intake of lipids and synthesis of triglycerides in adipocytes Other anabolic effects Glucagon (Also Primarily) | a Islet cells | glycogenolysis and gluconeogenesis in liver increases blood glucose level Somatostatin | d Islet cells | Inhibit release of insulin[11] Inhibit release of glucagon[11] Suppress the exocrine secretory action of pancreas. Pancreatic polypeptide | PP cells | Unknown Kidney Secreted hormone | From cells | Effect Renin (Primarily) | Juxtaglomerular cells | Activates the renin-angiotensin system by producing angiotensin I of angiotensinogen Erythropoietin (EPO) | Extraglomerular mesangial cells | Stimulate erythrocyte production Calcitriol (1,25-dihydroxyvitamin D3) | Active form of vitamin D3 Increase absorption of calcium and phosphate from gastrointestinal tract and kidneys inhibit release of PTH Thrombopoietin | stimulates megakaryocytes to produce platelets[7] Adrenal glands Adrenal cortex Secreted hormone | From cells | Effect Glucocorticoids (chiefly cortisol) | zona fasciculata and zona reticularis cells | Stimulation of gluconeogenesis Inhibition of glucose uptake in muscle and adipose tissue Mobilization of amino acids from extrahepatic tissues Stimulation of fat breakdown in adipose tissue anti-inflammatory and immunosuppressive Mineralocorticoids (chiefly aldosterone) | Zona glomerulosa cells | Increase blood volume by reabsorption of sodium in kidneys (primarily) Potassium and H+ secretion in kidney. Androgens (including DHEA and testosterone) | Zona fasciculata and Zona reticularis cells | Virilization, anabolic Adrenal medulla Secreted hormone | From cells | Effect Adrenaline (epinephrine) (Primarily) | Chromaffin cells | Fight-or-flight response: Boost the supply of oxygen and glucose to the brain and muscles (by increasing heart rate and stroke volume, vasodilation, increasing catalysis of glycogen in liver, breakdown of lipids in fat cells) Dilate the pupils Suppress non-emergency bodily processes (e.g., digestion) Suppress immune system Noradrenaline (norepinephrine) | Chromaffin cells | Fight-or-flight response: Boost the supply of oxygen and glucose to the brain and muscles (by increasing heart rate and stroke volume, vasoconstriction and increased blood pressure, breakdown of lipids in fat cells) Increase skeletal muscle readiness. Dopamine | Chromaffin cells | Increase heart rate and blood pressure Enkephalin | Chromaffin cells | Regulate pain Testes Secreted hormone | From cells | Effect Androgens (chiefly testosterone) | Leydig cells | Anabolic: growth of muscle mass and strength, increased bone density, growth and strength, Virilizing: maturation of sex organs, formation of scrotum, deepening of voice, growth of beard and axillary hair. Estradiol | Sertoli cells | Prevent apoptosis of germ cells[12] Inhibin | Sertoli cells | Inhibit production of FSH Ovary These originate either from the ovarian follicle or the corpus luteum. Secreted hormone | From cells | Effect Progesterone | Granulosa cells, theca cells | Support pregnancy[13]: Convert endometrium to secretory stage Make cervical mucus permeable to sperm. Inhibit immune response, e.g., towards the human embryo Decrease uterine smooth muscle contractility[13] Inhibit lactation Inhibit onset of labor. Other: Raise epidermal growth factor-1 levels Increase core temperature during ovulation[14] Reduce spasm and relax smooth muscle (widen bronchi and regulate mucus) Anti-inflammatory Reduce gall-bladder activity[15] Normalize blood clotting and vascular tone, zinc and copper levels, cell oxygen levels, and use of fat stores for energy Assist in thyroid function and bone growth by osteoblasts Increase resilience in bone, teeth, gums, joint, tendon, ligament, and skin Promote healing by regulating collagen Provide nerve function and healing by regulating myelin Prevent endometrial cancer by regulating effects of estrogen Androstenedione | Theca cells | Substrate for estrogen Estrogens (mainly estradiol) | Granulosa cells | Structural: Promote formation of female secondary sex characteristics Accelerate height growth Accelerate metabolism (burn fat) Reduce muscle mass Stimulate endometrial growth Increase uterine growth Maintain blood vessels and skin Reduce bone resorption, increase bone formation Protein synthesis: Increase hepatic production of binding proteins Coagulation: Increase circulating level of factors 2, 7, 9, 10, antithrombin III, plasminogen Increase platelet adhesiveness Increase HDL, triglyceride, height growth Decrease LDL, fat deposition Fluid balance: Regulate salt (sodium) and water retention Increase growth hormone Increase cortisol, SHBG Gastrointestinal tract: Reduce bowel motility Increase cholesterol in bile Melanin: Increase pheomelanin, reduce eumelanin Cancer: Support hormone-sensitive breast cancers [16] (Suppression of production in the body of estrogen is a treatment for these cancers.) Lung function: Promote lung function by supporting alveoli.[17] Inhibin | Granulosa cells | Inhibit production of FSH from anterior pituitary Placenta (when pregnant) Secreted hormone | Abbreviation | From cells | Effect Progesterone (Primarily) | Support pregnancy[13]: Inhibit immune response, towards the fetus. Decrease uterine smooth muscle contractility[13] Inhibit lactation Inhibit onset of labor. Support fetal production of adrenal mineralo- and glucosteroids. Other effects on mother similar to ovarian follicle-progesterone Estrogens (mainly Estriol) (Also Primarily) | Effects on mother similar to ovarian follicle estrogen Human chorionic gonadotropin | HCG | Syncytiotrophoblast | promote maintenance of corpus luteum during beginning of pregnancy Inhibit immune response, towards the human embryo. Human placental lactogen | HPL | Syncytiotrophoblast | increase production of insulin and IGF-1 increase insulin resistance and carbohydrate intolerance Inhibin | Fetal Trophoblasts | suppress FSH Uterus (when pregnant) Secreted hormone | Abbreviation | From cells | Effect Prolactin | PRL | Decidual cells | milk production in mammary glands Relaxin | Decidual cells | Unclear in humans and animals
References ^ Collier, Judith. et.al (2006). Oxford Handbook of Clinical Specialties 7th edn.. Oxford. pp. –1. ISBN 0-19-853085-4. ^ University of Virginia - HISTOLOGY OF THE ENDOCRINE GLANDS ^ Kasper et al. (2005). Harrison's Principles of Internal Medicine. McGraw Hill. pp. . ISBN 0-07-139140-1. ^ Bhowmick NA, Chytil A, Plieth D, et al (February 2004). "TGF-beta signaling in fibroblasts modulates the oncogenic potential of adjacent epithelia". Science 303 (5659): 848–51. doi:10.1126/science.1090922. PMID 14764882. ^ a b Kosfeld M, Heinrichs M, Zak PJ, Fischbacher U, Fehr E (June 2005). "Oxytocin increases trust in humans" . Nature 435 (7042): 673–6. doi:10.1038/nature03701. PMID 15931222. http://www.iew.unizh.ch/home/kosfeld/papers/ottrust_nature.pdf. ^ a b Kraft U (Jun/July 2007). "Rhythm and Blues". Scientific American Mind. http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview&ARTICLEID_CHAR=C001082B-2B35-221B-641CA6ED64E8BCF3. ^ a b c Kaushansky K (May 2006). "Lineage-specific hematopoietic growth factors". N Engl J Med. 354 (19): 2034–45. doi:10.1056/NEJMra052706. PMID 16687716. ^ Frьhbeck G (July 2004). "The adipose tissue as a source of vasoactive factors". Curr Med Chem Cardiovasc Hematol Agents 2 (3): 197–208. doi:10.2174/1568016043356255. PMID 15320786. http://openurl.ingenta.com/content/nlm?genre=article&issn=1568-0169&volume=2&issue=3&spage=197&aulast=Frьhbeck. ^ Colorado State University - Biomedical Hypertextbooks - Somatostatin ^ Endo K, Matsumoto T, Kobayashi T, Kasuya Y, Kamata K (February 2005). "Diabetes-related changes in contractile responses of stomach fundus to endothelin-1 in streptozotocin-induced diabetic rats" ([dead link] – Scholar search). J Smooth Muscle Res 41 (1): 35–47. doi:10.1540/jsmr.41.35. PMID 15855738. http://joi.jlc.jst.go.jp/JST.JSTAGE/jsmr/41.35?from=PubMed. ^ a b Physiology at MCG 5/5ch4/s5ch4_17 ^ Pentikдinen V, Erkkilд K, Suomalainen L, Parvinen M, Dunkel L (May 2000). "Estradiol acts as a germ cell survival factor in the human testis in vitro". J Clin Endocrinol Metab. 85 (5): 2057–67. doi:10.1210/jc.85.5.2057. PMID 10843196. http://jcem.endojournals.org/cgi/pmidlookup?view=long&pmid=10843196. ^ a b c d Placental Hormones ^ Physiology at MCG 5/5ch9/s5ch9_13 ^ Hould F, Fried G, Fazekas A, Tremblay S, Mersereau W (1988). "Progesterone receptors regulate gallbladder motility". J Surg Res 45 (6): 505–12. doi:10.1016/0022-4804(88)90137-0. PMID 3184927. ^ Hormonal Therapy ^ Massaro D, Massaro GD (2004). "Estrogen regulates pulmonary alveolar formation, loss, and regeneration in mice". American Journal of Physiology. Lung Cellular and Molecular Physiology 287 (6): L1154–9. doi:10.1152/ajplung.00228.2004. PMID 15298854. http://en.wikipedia.org/wiki/Endocrine_system
Рефераты по иностранным языкамContents 1 Function 1.1 Types of signaling 1.1.1 Endocrine 1.1.2 Autocrine 1.1.3 Paracrine 1.1.4 Juxtacrine 2 Role in disease 3 Table of endocrine
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