Hormone Wiki - What is the hormone?
A hormone (from the Greek participle “ὁρμῶ”, "to set in motion, urge on") is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). The glands that secrete hormones comprise the endocrine signaling system. The term hormone is sometimes extended to include chemicals produced by cells that affect the same cell (autocrine or intracrine signalling) or nearby cells (paracrine signalling). Hormones are used to communicate between organs and tissues for physiological regulation and behavioral activities, such as digestion, metabolism, respiration, tissue function, sensory perception, sleep, excretion, lactation, stress, growth and development, movement, reproduction, and mood. Hormones affect distant cells by binding to specific receptor proteins in the target cell resulting in a change in cell function. When a hormone binds to the receptor, it results in the activation of a signal transduction pathway that typically activates gene transcription resulting in increased expression of target proteins; non-genomic effects are more rapid, and can be synergistic with genomic effects. Amino acid–based hormones (amines and peptide or protein hormones) are water-soluble and act on the surface of target cells via second messengers; steroid hormones, being lipid-soluble, move through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei. Hormone secretion may occur in many tissues. Endocrine glands are the cardinal example, but specialized cells in various other organs also secrete hormones. Hormone secretion occurs in response to specific biochemical signals from a wide range of regulatory systems. For instance, serum calcium concentration affects parathyroid hormone synthesis; blood sugar (serum glucose concentration) affects insulin synthesis; and because the outputs of the stomach and exocrine pancreas (the amounts of gastric juice and pancreatic juice) become the input of the small intestine, the small intestine secretes hormones to stimulate or inhibit the stomach and pancreas based on how busy it is. Regulation of hormone synthesis of gonadal hormones, adrenocortical hormones, and thyroid hormones is often dependent on complex sets of direct influence and feedback interactions involving the hypothalamic-pituitary-adrenal (HPA), -gonadal (HPG), and -thyroid (HPT) axes. Upon secretion, certain hormones, including protein hormones and catecholamines, are water-soluble and are thus readily transported through the circulatory system. Other hormones, including steroid and thyroid hormones, are lipid-soluble; to allow for their widespread distribution, these hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes. Some hormones are completely active when released into the bloodstream (as is the case for insulin and growth hormones), while others are prohormones that must be activated in specific cells through a series of activation steps that are commonly highly regulated. The endocrine system secretes hormones directly into the bloodstream, typically via fenestrated capillaries, whereas the exocrine system secretes its hormones indirectly using ducts. Hormones with paracrine function diffuse through the interstitial spaces to nearby target tissue..
What does the word hormone mean? Find synonyms, antonyms and the meaning of the word hormone in our free online dictionary! Find words starting with hormone and anagrams of hormone.
Definitions of "hormone"
- A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism. noun
- A synthetic compound that acts like a hormone in the body. noun
- Any of various similar substances found in plants and insects that regulate development. noun
- Any substance produced by one tissue and conveyed by the bloodstream to another to effect physiological activity. noun
- A synthetic compound with the same activity. noun
- Any similar substance in plants. noun
- A chemical substance formed in one organ and carried in the circulation to another organ on which it exerts a specific effect on cells at a distance from the producing cells. noun
- a chemical substance, whether natural or synthetic, that functions like a hormone in a living organism. . noun
- A substance that controls growth rate or differentiation in plants; also called phytohormone. The most well-known are the auxins that stimulate growth at the growing tips of plants, and control root formation and the dropping of leaves; and the gibberellins, which are used in agriculture to promote plant growth. noun
- the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect noun
The word "hormone" in example sentences
Doctors previously used the term hormone-replacement therapy (HRT), which carried the connotation that menopausal women were missing something essential.. [The Seattle Times]
We believe students need a break from what I call "hormone display behavior" which can be exhausting for adolescents.. [Meg Campbell: Laughter, Joy and Friendship in School?]
However, Jobs took a six-month leave of absence in early 2009 for what he called a "hormone imbalance.". [Apple Co-Founder Steve Jobs Dies at 56]
This hormone is the ultimate 'feel good' chemical because it is the essence of love, friendship, and tolerance of others.. [yalla - French Word-A-Day]
Apple executives provided no additional information on the well-being of CEO Steve Jobs, who stepped away from day-to-day operations in January to get treated for what he called a hormone imbalance.. 
Apple's Jobs: Hormone Condition Won't Hinder CEO Duties letter released today, Apple (NASDAQ: AAPL) CEO Steve Jobs sought to dispel some of the persistent rumors surrounding his health -- while admitting that he's recovering from what he described as a hormone imbalance.. [InternetNews Realtime News for IT Managers]
We know African-Americans are diagnosed at younger ages with what we call hormone-sensitive cancers, like prostate and breast cancer.. [News for WSAV]
In 2003, Dr. Gershon Ejeckam wrote a series of memos in which he dubbed hormone receptor testing erratic, unreliable and unhelpful.. [The Telegram: National News]
The new findings indicate the drop in hormone use will probably speed that, Chlebowski and others said.. [Study: Hormones up breast cancer deaths]
Can certain hormone combinations increase the relative ratios of certain chromosones in sperm and move certain ova ahead in que?. [Dysculturation?, Bryan Caplan | EconLog | Library of Economics and Liberty]
The FDA therefore concluded that there was no relevant difference in hormone levels in GE salmon.. [Jeffrey Smith: GE Salmon? Are You Out of Your Minds?!]
Endocrinologists specialize in hormone imbalances and are the treating specialist for diabetes.. [Riva Greenberg: The Urgent State of Diabetes]
I attribute this to: any changes in hormone levels will cause hot flashes.. [Oprah's Talking Hormones]
Tiny changes in hormone levels cause vast changes in the body's chemistry, or synergism.. [Dr. Richard Palmquist: Veterinarians Team With Mother Nature for Better Results]
It's the way the couples disagreed that was later related to a rise in hormone levels and a drop in immune function.. [Ronald Alexander, Ph.D.: Resolving Arguments in the Bedroom and the Boardroom]
Estrogen doses in hormone replacement are much lower than in contraceptives.. [Seven Things To Know About Hormones - My Take]
Hormone TranslatesHormone English to Turkish Translate
i. hormon.i. hormon.