Endocrine system main organs and functions. Endocrine System: Functions, Organs, and Conditions Explained
What are the main organs of the endocrine system. How does the endocrine system function in the human body. What are common endocrine disorders and their symptoms. How do hormones regulate bodily processes. What is the difference between endocrine and exocrine glands. How do endocrine diseases affect overall health. What are the latest treatments for endocrine disorders.
The Endocrine System: An Overview of Hormonal Regulation
The endocrine system plays a crucial role in maintaining homeostasis within the human body. It consists of a network of glands that produce and secrete hormones directly into the bloodstream. These chemical messengers regulate various bodily functions, including metabolism, growth, development, reproduction, and mood.
How does the endocrine system differ from other bodily systems? Unlike the nervous system, which uses electrical impulses to transmit information quickly, the endocrine system relies on hormones carried through the bloodstream to deliver messages more slowly but with longer-lasting effects.
Key Components of the Endocrine System
- Glands: Specialized organs that produce and secrete hormones
- Hormones: Chemical messengers that regulate bodily functions
- Receptors: Proteins on target cells that bind to specific hormones
- Feedback loops: Mechanisms that maintain hormone balance
Major Endocrine Glands and Their Functions
The endocrine system comprises several glands distributed throughout the body. Each gland produces specific hormones that target particular organs or tissues. What are the primary endocrine glands and their roles?
Pituitary Gland: The Master Regulator
Often referred to as the “master gland,” the pituitary gland is located at the base of the brain. It produces hormones that control the function of other endocrine glands and regulates various bodily processes.
Key pituitary hormones include:
- Growth hormone (GH): Promotes growth and cell reproduction
- Adrenocorticotropic hormone (ACTH): Stimulates the adrenal glands
- Thyroid-stimulating hormone (TSH): Regulates thyroid gland function
- Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH): Control reproductive functions
Thyroid Gland: Metabolism and Energy Regulation
The butterfly-shaped thyroid gland in the neck produces hormones that regulate metabolism, energy production, and body temperature. How do thyroid hormones impact daily life?
Thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), influence:
- Basal metabolic rate
- Heart rate and blood pressure
- Body temperature
- Nervous system function
- Growth and development
Adrenal Glands: Stress Response and Electrolyte Balance
Located atop the kidneys, the adrenal glands produce hormones that help the body respond to stress and maintain electrolyte balance. What are the key adrenal hormones and their functions?
- Cortisol: Regulates metabolism and immune response
- Aldosterone: Controls sodium and potassium balance
- Adrenaline and noradrenaline: Mediate the “fight or flight” response
Hormonal Signaling: The Language of the Endocrine System
Hormones act as chemical messengers, transmitting signals from endocrine glands to target cells throughout the body. How do these signals work, and what types of signaling exist within the endocrine system?
Endocrine Signaling
The primary mode of communication in the endocrine system is endocrine signaling. In this process, hormones are released into the bloodstream and travel to distant target cells, where they bind to specific receptors and trigger cellular responses.
Paracrine and Autocrine Signaling
In addition to endocrine signaling, the endocrine system also utilizes paracrine and autocrine signaling. What’s the difference between these modes of communication?
- Paracrine signaling: Hormones act on nearby cells
- Autocrine signaling: Hormones affect the same cell that produced them
Neuroendocrine Signaling
Neuroendocrine signaling involves the interaction between the nervous and endocrine systems. Certain neurons in the brain, such as those in the hypothalamus, can release hormones directly into the bloodstream, blurring the line between neural and endocrine communication.
Endocrine Axes: Coordinated Hormone Cascades
Endocrine glands often work together in sequences known as axes. These coordinated hormone cascades ensure precise regulation of bodily functions. What are some important endocrine axes?
Hypothalamic-Pituitary-Adrenal (HPA) Axis
The HPA axis plays a crucial role in the body’s stress response. It involves the following sequence:
- The hypothalamus releases corticotropin-releasing hormone (CRH)
- CRH stimulates the anterior pituitary to produce adrenocorticotropic hormone (ACTH)
- ACTH triggers the adrenal glands to release cortisol
- Cortisol provides negative feedback to the hypothalamus and pituitary, regulating the axis
Hypothalamic-Pituitary-Thyroid (HPT) Axis
The HPT axis regulates thyroid function and metabolism. Its components include:
- Thyrotropin-releasing hormone (TRH) from the hypothalamus
- Thyroid-stimulating hormone (TSH) from the anterior pituitary
- Thyroid hormones (T3 and T4) from the thyroid gland
Endocrine Disorders: When Hormones Go Awry
Endocrine disorders occur when glands produce too much or too little of a hormone, or when the body doesn’t respond properly to hormones. These conditions can have wide-ranging effects on health and well-being. What are some common endocrine disorders?
Diabetes Mellitus
Diabetes is a group of metabolic disorders characterized by high blood sugar levels. The two main types are:
- Type 1 diabetes: An autoimmune condition where the body doesn’t produce insulin
- Type 2 diabetes: A metabolic disorder involving insulin resistance and insufficient insulin production
Thyroid Disorders
Thyroid dysfunction can lead to various health issues. Common thyroid disorders include:
- Hypothyroidism: Underactive thyroid gland
- Hyperthyroidism: Overactive thyroid gland
- Goiter: Enlarged thyroid gland
- Thyroid nodules: Growths within the thyroid gland
Adrenal Disorders
Disorders affecting the adrenal glands can disrupt the body’s stress response and electrolyte balance. Examples include:
- Addison’s disease: Adrenal insufficiency
- Cushing’s syndrome: Excess cortisol production
- Pheochromocytoma: Tumor of the adrenal medulla
Diagnosing and Treating Endocrine Disorders
Endocrine disorders can be challenging to diagnose due to their complex nature and often overlapping symptoms. How are these conditions identified and managed?
Diagnostic Approaches
Endocrinologists use various methods to diagnose hormonal imbalances:
- Blood and urine tests to measure hormone levels
- Imaging studies (e.g., ultrasound, CT, MRI) to visualize endocrine glands
- Genetic testing for inherited endocrine disorders
- Stimulation or suppression tests to assess gland function
Treatment Options
Treatment for endocrine disorders aims to restore hormonal balance and alleviate symptoms. Common approaches include:
- Hormone replacement therapy
- Medications to suppress or stimulate hormone production
- Lifestyle modifications (diet, exercise, stress management)
- Surgery to remove tumors or dysfunctional glands
- Radiation therapy for certain endocrine cancers
The Endocrine System and Cancer
The relationship between the endocrine system and cancer is complex and multifaceted. How do hormones influence cancer development and progression?
Hormone-Dependent Cancers
Some cancers are sensitive to hormones and may grow or spread more rapidly in their presence. Examples include:
- Breast cancer: Often influenced by estrogen and progesterone
- Prostate cancer: Typically androgen-dependent
- Thyroid cancer: May be affected by thyroid-stimulating hormone (TSH)
Endocrine Gland Tumors
Tumors can develop within endocrine glands themselves, leading to hormone overproduction or underproduction. Some examples are:
- Pituitary adenomas
- Thyroid nodules and thyroid cancer
- Adrenal tumors
- Pancreatic neuroendocrine tumors
Hormonal Therapy in Cancer Treatment
Understanding the relationship between hormones and cancer has led to the development of hormonal therapies for certain types of cancer. These treatments work by:
- Blocking hormone production
- Interfering with hormone action
- Altering hormone receptor function
Emerging Research and Future Directions in Endocrinology
The field of endocrinology continues to evolve, with new discoveries and treatment approaches emerging regularly. What are some exciting areas of ongoing research?
Precision Medicine in Endocrinology
Researchers are exploring ways to tailor endocrine treatments to individual patients based on their genetic makeup, lifestyle factors, and specific hormone profiles. This personalized approach may lead to more effective and targeted therapies for endocrine disorders.
Endocrine Disruptors and Environmental Health
There is growing concern about the impact of environmental chemicals on the endocrine system. Studies are investigating how these endocrine disruptors affect hormone function and contribute to various health issues, including developmental disorders, reproductive problems, and certain cancers.
Artificial Intelligence in Endocrine Diagnosis
Machine learning algorithms are being developed to assist in the diagnosis and management of endocrine disorders. These AI-powered tools may help clinicians interpret complex hormone data and identify subtle patterns that could indicate early-stage endocrine dysfunction.
Neuroendocrine Interactions and Mental Health
Researchers are delving deeper into the connections between the endocrine and nervous systems, exploring how hormonal imbalances may contribute to mental health disorders such as depression, anxiety, and cognitive decline. This research may lead to new treatment approaches that target both hormonal and neurological factors.
Gene Therapy for Endocrine Disorders
Advances in gene editing technologies, such as CRISPR-Cas9, are opening up new possibilities for treating genetic endocrine disorders. Scientists are exploring ways to correct faulty genes responsible for conditions like congenital adrenal hyperplasia and certain forms of diabetes.
The endocrine system’s intricate network of glands and hormones plays a vital role in maintaining our health and well-being. As our understanding of this complex system continues to grow, so too does our ability to diagnose, treat, and prevent endocrine disorders. From personalized medicine approaches to cutting-edge gene therapies, the future of endocrinology holds great promise for improving the lives of millions affected by hormonal imbalances and related conditions.
Endocrine system – wikidoc
Major endocrine glands. (Male left, female on the right.) 1.Pineal gland2.Pituitary gland3.Thyroid gland4.Thymus5.Adrenal gland6.Pancreas7.Ovary8.Testes
Editors-In-Chief: C. Michael Gibson, M.S., M.D. [1] and Stephanie Fernandez, M.D. [2]
The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, growth and development and puberty, tissue function, and plays a part also in mood.[1]
The field of medicine that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine.
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
Main article: Autocrine signalling
Other signaling can target the same cell.
Paracrine
Main article: Paracrine signalling
Paracrine signaling is where the target cell is nearby.
Juxtacrine
Main article: Juxtacrine signalling
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
Main article: Endocrine diseases
Diseases of the endocrine system are common,[3] including diseases such as diabetes mellitus, thyroid disease, and obesity.
Endocrine disease is characterised by dysregulated hormone release (a productive Pituitary adenoma), inappropriate response to signalling (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 result of loss of reserve, hyposecretion, agenesis, atrophy, or active destruction. Hyperfunction can occur as 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 signalling distant tissues to proliferate, for example the Estrogen receptor has been shown to be involved in certain breast cancers. Endocrine, Paracrine, and autocrine signalling have all been implicated in proliferation, one of the required steps of oncogenesis.[4]
Table of endocrine glands and secreted hormones
This is a table of the glands of the endocrine system, and their 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 |
Vasopressin | Parvocellular neurosecretory neurons | Release ACTH from anterior pituitary | |
Somatostatin, also growth hormone-inhibiting hormone | SS or GHIH | Neuroendocrince cells of the Periventricular nucleus | Inhibit release of GH and TRH from anterior pituitary |
Prolactin inhibiting hormone or Dopamine | PIH or DA | Dopamine neurons of the arcuate nucleus | Inhibit release of prolactin and TRH from anterior pituitary |
Prolactin-releasing hormone | PRH | Release prolactin from anterior pituitary |
Pineal body
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)
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]. | |
Vasopressin or antidiuretic hormone | AVP or ADH | Magnocellular neurosecretory cells | retention of water in kidneys moderate vasoconstriction |
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 |
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
(Slightly) decrease blood phosphate:
|
Heart
Secreted hormone | Abbreviation | From cells | Effect |
---|---|---|---|
Atrial-natriuretic peptide | ANP | Cardiac myocytes | Reduce blood pressure by: reducing systemic vascular resistance, |
Brain natriuretic peptide | BNP | Cardiac myocytes | (To a minor degree than ANP) reduce blood pressure by: reducing systemic vascular resistance, |
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 | |
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 | |
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 |
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 | |
Thrombopoietin | Hepatocytes | stimulates megakaryocytes to produce platelets[7] |
Pancreas
Secreted hormone | From cells | Effect |
---|---|---|
Insulin (Primarily) | ß Islet cells | Intake of glucose, glycogenesis and glycolysis in liver and muscle from blood intake of lipids and synthesis of triglycerides in adipocytes |
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] |
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 | |
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 |
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:
|
Noradrenaline (norepinephrine) | Chromaffin cells | Fight-or-flight response:
|
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]:
Other:
Anti-inflammatory
|
Androstenedione | Theca cells | Substrate for estrogen |
Estrogens (mainly estradiol) | Granulosa cells | Structural:
Protein synthesis:
Coagulation:
Fluid balance:
Gastrointestinal tract:
Melanin:
Cancer:
Lung function:
|
Inhibin | Granulosa cells | Inhibit production of FSH from anterior pituitary |
Placenta (when pregnant)
Secreted hormone | Abbreviation | From cells | Effect |
---|---|---|---|
Progesterone (Primarily) | Support pregnancy[13]:
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 |
See also
- Releasing hormones
- Neuroendocrinology
- Nervous system
- Endocrine disruptor
- Major systems of the human body
Links
- Journals Designed for Clinical Endocrinologists
- Islet cell antibody
- Binding of antibody to pancreas
- Kidshealth. org
References
- ↑ Collier, Judith. et.al (2006). Oxford Handbook of Clinical Specialties 7th edn. Oxford. pp. 350–351. 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. p. 2074. ISBN 0-07-139140-1.CS1 maint: Explicit use of et al. (link)
- ↑ Bhowmick NA, Chytil A, Neilson EG, Moses HL (2004). “TGF-beta signaling in fibroblasts modulates the oncogenic potential of adjacent epithelia”. Science. Feb 6 303(5659): 848–51.CS1 maint: Multiple names: authors list (link)
- ↑ Kosfeld M et al. (2005) Oxytocin increases trust in humans. Nature 435:673-676. PDF PMID 15931222
- ↑ Scientific American Mind, “Rhythm and Blues”; June/July 2007; Scientific American Mind; by Ulrich Kraft
- ↑ 7.07.17.2 Kaushansky K. Lineage-specific hematopoietic growth factors. N Engl J Med 2006;354:2034-45. PMID 16687716.
- ↑ The adipose tissue as a source of vasoactive factors. Frühbeck G. (Curr Med Chem Cardiovasc Hematol Agents. 2004 Jul;2(3):197-208.)
- ↑ http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/otherendo/somatostatin.html Colorado State University – Biomedical Hypertextbooks – Somatostatin
- ↑ Diabetes-related changes in contractile responses of stomach fundus to endothelin-1 in streptozotocin-induced diabetic rats Journal of Smooth Muscle Research Vol. 41 (2005) , No. 1 35-47. Kazuki Endo1), Takayuki Matsumoto1), Tsuneo Kobayashi1), Yutaka Kasuya1) and Katsuo Kamata1)
- ↑ 11.011.1Essentials of Human Physiology by Thomas M. Nosek. Section 5/5ch5/s5ch5_17.
- ↑ Pentikäinen V, Erkkilä K, Suomalainen L, Parvinen M, Dunkel L. Estradiol Acts as a Germ Cell Survival Factor in the Human Testis in vitro.
The Journal of Clinical Endocrinology & Metabolism 2006;85:2057-67 PMID 10843196 - ↑ 13. 013.113.213.3http://www.vivo.colostate.edu/hbooks/pathphys/reprod/placenta/endocrine.html
- ↑ Essentials of Human Physiology by Thomas M. Nosek. Section 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. PMID 3184927.CS1 maint: Multiple names: authors list (link)
- ↑ http://www.breastcancer.org/tre_sys_hrt_idx.html
- ↑ 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. PMID 15298854 url=http://ajplung.physiology.org/cgi/content/full/287/6/L1154.CS1 maint: Missing pipe (link)
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Что это такое, функции, органы и состояния
Эндокринная система представляет собой сеть желез и органов, расположенных по всему телу. Она похожа на нервную систему тем, что играет жизненно важную роль в контроле и регулировании многих функций организма.
Однако, в то время как нервная система использует нервные импульсы и нейротрансмиттеры для связи, эндокринная система использует химические мессенджеры, называемые гормонами.
Продолжайте читать, чтобы узнать больше об эндокринной системе, ее функциях и вырабатываемых ею гормонах.
Эндокринная система отвечает за регулирование целого ряда функций организма посредством выделения гормонов.
Гормоны выделяются железами эндокринной системы, попадая с током крови в различные органы и ткани организма. Затем гормоны сообщают этим органам и тканям, что делать или как функционировать.
Некоторые примеры функций организма, которые контролируются эндокринной системой, включают:
- метаболизм
- рост и развитие
- половая функция и репродуктивная функция
- частота сердечных сокращений
- кровяное давление
- аппетит
- циклы сна и бодрствования
- температура тела
Что такое железа?
Железа — это орган, который вырабатывает и выделяет вещества, необходимые организму для функционирования. Существует два типа желез:
- эндокринные железы , которые выделяют гормоны непосредственно в кровоток
- экзокринные железы , такие как лимфатические узлы и потовые железы, которые не являются частью эндокринной системы
В железах эндокринной системы вырабатываются, хранятся и высвобождаются гормоны. Каждая железа вырабатывает один или несколько гормонов, которые воздействуют на определенные органы и ткани организма.
К железам эндокринной системы относятся:
- Гипоталамус. Хотя некоторые люди не считают его железой, гипоталамус вырабатывает несколько гормонов, которые контролируют работу гипофиза. Он также участвует в регулировании многих функций, включая циклы сна и бодрствования, температуру тела и аппетит. Он также может регулировать функцию других эндокринных желез.
- Гипофиз. Гипофиз расположен ниже гипоталамуса. Вырабатываемые им гормоны влияют на рост и размножение. Они также могут контролировать функцию других эндокринных желез.
- Пинеальная железа. Эта железа находится в середине вашего мозга. Это важно для ваших циклов сна и бодрствования.
- Щитовидная железа. Щитовидная железа расположена в передней части шеи. Это очень важно для обмена веществ.
- Паращитовидная железа. Паращитовидная железа, также расположенная в передней части шеи, важна для контроля уровня кальция в костях и крови.
- Тимус. Вилочковая железа, расположенная в верхней части туловища, активна до полового созревания и вырабатывает гормоны, важные для развития типа лейкоцитов, называемых Т-клетками.
- Надпочечники. Над каждой почкой расположено по одному надпочечнику. Эти железы вырабатывают гормоны, которые важны для регулирования таких функций, как артериальное давление, частота сердечных сокращений и реакция на стресс.
- Поджелудочная железа. Поджелудочная железа расположена в брюшной полости за желудком. Его эндокринная функция включает контроль уровня сахара в крови.
Некоторые эндокринные железы также выполняют неэндокринные функции. Например, яичники и яички вырабатывают гормоны, но они также выполняют неэндокринную функцию производства яйцеклеток и сперматозоидов соответственно.
Гормоны — это химические вещества, которые эндокринная система использует для отправки сообщений органам и тканям по всему телу. После выброса в кровоток гормоны перемещаются к органу или ткани-мишени, имеющим рецепторы, которые распознают гормон и реагируют на него.
Ниже приведены некоторые примеры гормонов, вырабатываемых эндокринной системой.
Гормон | Секретирующая железа (S) | Функция | ||||||||||||||||||||||||||||||||||||||||||||||
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АДРЕРРИН | ||||||||||||||||||||||||||||||||||||||||||||||||
ADRENLIN альдостерон | надпочечники | контролирует водно-солевой баланс организма | ||||||||||||||||||||||||||||||||||||||||||||||
cortisol | adrenal | plays a role in stress response | ||||||||||||||||||||||||||||||||||||||||||||||
dehydroepiandrosterone sulfate (DHEA-S) | adrenal | aids in production of body odor and growth of body hair during puberty | ||||||||||||||||||||||||||||||||||||||||||||||
estrogen | яичник | способствует регулированию менструального цикла, сохранению беременности и развитию женских половых признаков; способствует выработке спермы | ||||||||||||||||||||||||||||||||||||||||||||||
фолликулостимулирующий гормон (ФСГ) | Гипофик | контролирует производство яиц и сперма | ||||||||||||||||||||||||||||||||||||||||||||||
Глюкагон | Панкроаз | Помогает уровни глюкозы в крови (кровя) | ||||||||||||||||||||||||||||||||||||||||||||||
Инсульин | ||||||||||||||||||||||||||||||||||||||||||||||||
лютеинизирующий гормон (ЛГ) | гипофиз | контролирует выработку эстрогена и тестостерона, а также овуляцию | ||||||||||||||||||||||||||||||||||||||||||||||
мелатонин | pineal | controls sleep-wake cycles | ||||||||||||||||||||||||||||||||||||||||||||||
oxytocin | pituitary | helps with lactation, childbirth, and mother-child bonding | ||||||||||||||||||||||||||||||||||||||||||||||
parathyroid hormone | parathyroid | controls calcium levels in bones and blood | ||||||||||||||||||||||||||||||||||||||||||||||
прогестерон | яичник | помогает подготовить организм к беременности при оплодотворении яйцеклетки | ||||||||||||||||||||||||||||||||||||||||||||||
пролактин | гипофиз | способствует выработке грудного молока | ||||||||||||||||||||||||||||||||||||||||||||||
тестостерон | яичники, яички, надпочечники | способствует половому влечению и плотности тела у мужчин и женщин, а также развитию мужских половых признаков | ||||||||||||||||||||||||||||||||||||||||||||||
09 гормон щитовидной железы | помогает контролировать несколько функций организма, в том числе скорость метаболизма и уровень энергии. Иногда уровень гормонов может быть слишком высоким или слишком низким. Когда это происходит, это может иметь ряд последствий для вашего здоровья. Признаки и симптомы зависят от дисбаланса гормона. Ниже приведены некоторые состояния, которые могут повлиять на эндокринную систему и изменить уровень гормонов. ГипертиреозГипертиреоз возникает, когда щитовидная железа вырабатывает больше гормонов щитовидной железы, чем необходимо. Это может быть вызвано рядом вещей, включая аутоиммунные заболевания. Некоторые распространенные симптомы гипертиреоза включают:
. а также его первопричина. Варианты включают лекарства, радиойодтерапию или хирургическое вмешательство. Болезнь Грейвса является аутоиммунным заболеванием и распространенной формой гипертиреоза. У людей с болезнью Грейвса иммунная система атакует щитовидную железу, что заставляет ее вырабатывать больше гормонов щитовидной железы, чем обычно. ГипотиреозГипотиреоз возникает, когда щитовидная железа не вырабатывает достаточного количества гормонов щитовидной железы. Подобно гипертиреозу, он имеет много потенциальных причин. Some common symptoms of hypothyroidism include: Treatment for гипотиреоз предполагает добавление гормонов щитовидной железы с помощью лекарств. Синдром КушингаСиндром Кушинга возникает из-за высокого уровня гормона кортизола. Общие симптомы синдрома Кушинга включают: Лечение зависит от причины заболевания и может включать прием лекарств, лучевую терапию или хирургическое вмешательство. Болезнь АддисонаБолезнь Аддисона возникает, когда ваши надпочечники не производят достаточного количества кортизола или альдостерона. Некоторые симптомы болезни Аддисона включают: Лечение болезни Аддисона включает прием лекарств, помогающих заменить гормоны, которые организм не вырабатывает в достаточном количестве. ДиабетДиабет относится к состоянию, при котором уровень сахара в крови не регулируется в определенном диапазоне. У людей с диабетом слишком много глюкозы в крови (высокий уровень сахара в крови). Существует два типа диабета: диабет 1 типа и диабет 2 типа. Некоторые распространенные симптомы диабета включают: Лечение диабета может включать инсулинотерапию, мониторинг крови и сахароснижающие препараты. Изменения в образе жизни, такие как регулярные физические упражнения и сбалансированное питание, также могут помочь. Синдром поликистозных яичников (СПКЯ)Это распространенное заболевание вызывается несбалансированными репродуктивными гормонами у людей с яичниками, что может вызвать проблемы с яичниками. Жизнь с СПКЯ может означать, что яйцеклетка не может выделяться каждый месяц или может развиваться не так, как должна, когда она выделяется. Некоторые из распространенных симптомов СПКЯ:
Лечение СПКЯ направлено на облегчение симптомов. Лечение включает лекарства, такие как противозачаточные средства и метформин, а также изменения образа жизни, такие как сосредоточение внимания на питании и попытки достичь умеренного веса, если ваш врач порекомендовал это. ГипогонадизмРаспространенное состояние, особенно у пожилых мужчин и иногда у женщин, гипогонадизм, вызванный пониженной выработкой полового гормона тестостерона. Это может привести к снижению либидо, а также к целому ряду других симптомов, таких как:
Лечение для гипогонадизма основное внимание уделяется повышению уровня тестостерона. Заместительная терапия тестостероном и изменение образа жизни (например, стремление к умеренному весу, если это порекомендовал врач) — два популярных метода. ОстеопорозОстеопороз — это аномальная потеря костной массы и изменения в костной ткани. Это может быть вызвано целым рядом проблем, но двумя распространенными причинами являются пониженный уровень эстрогена у людей с яичниками и пониженный уровень тестостерона у людей с яичками. Эти пониженные уровни гормонов могут быть вызваны возрастом, а также другими заболеваниями. Остеопороз не всегда вызывает явные симптомы. Но некоторые из наиболее распространенных симптомов — переломы костей и травмы, связанные с незначительными падениями, поднятием тяжестей и даже кашлем. Лечение остеопороза направлено на замедление или остановку потери костной массы. Правильное питание, физические упражнения и лекарства — три наиболее распространенных метода лечения. АкромегалияЭто редкое заболевание возникает, когда организм вырабатывает слишком много гормона роста, который в основном вырабатывается в гипофизе. В основном диагностируется у взрослых среднего возраста, может привести к увеличению размеров органов, костей, хрящей, органов и некоторых тканей. Общие симптомы акромегалии включают:
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