WordNet

the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli; "the doctor tested my tonicity" (同)tonus, tone
vary the pitch of ones speech (同)inflect, modulate
give a healthy elasticity to; "Lets tone our muscles" (同)tone up, strengthen
change the color or tone of; "tone a negative"
change to a color image; "tone a photographic image"
(linguistics) a pitch or change in pitch of the voice that serves to distinguish words in tonal languages; "the Beijing dialect uses four tones"
a steady sound without overtones; "they tested his hearing with pure tones of different frequencies" (同)pure tone
the quality of a persons voice; "he began in a conversational tone"; "he spoke in a nervous tone of voice" (同)tone of voice
a musical interval of two semitones (同)whole tone, step, whole step
the quality of something (an act or a piece of writing) that reveals the attitudes and presuppositions of the author; "the general tone of articles appearing in the newspapers is that the government should withdraw"; "from the tone of her behavior I gathe
utter monotonously and repetitively and rhythmically; "The students chanted the same slogan over and over again" (同)chant, intone
(of a solution) the extent to which a solution has a higher osmotic pressure than some other
lack of normal muscular tension or tonus (同)atony, atonia, amyotonia

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〈C〉(高さ・音色・長さ・音量の点から見た)『音』 / 〈C〉〈U〉音質 / 〈C〉楽音;全音程 / 〈C〉《しばしば複数形で》『言い方,書き方』,口調,語調 / 〈C〉支配的な(一般的な)風潮(傾向) / 〈U〉(筋肉などの緊張の)『正常な状態』 / 〈C〉『色調』,色合い,濃淡,明暗 / (音・色などで)…‘に'『ある調子(口調,色合い)をつける』 / …‘の'色を変える,色を補正する

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/12/14 22:44:10」(JST)

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"Hypotonic" redirects here. For the muscular disease, see Hypotonia.

Effect of different solutions on blood cells

Micrographs of osmotic pressure on red blood cells

Tonicity is a measure of the osmotic pressure gradient (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane. It is commonly used when describing the response of cells immersed in an external solution. Like osmotic pressure, tonicity is influenced only by solutes that cannot cross the membrane, as only these exert an osmotic pressure. Solutes able to freely cross the membrane do not affect tonicity because they will always be in equal concentrations on both sides of the membrane.

There are three classifications of tonicity that one solution can have relative to another. The three are hypertonic, hypotonic, and isotonic.^[1]

Hypertonicity[edit]

Hypertonic refers to a greater concentration. In biology, a hypertonic solution is one with a higher concentration of solutes outside the cell than inside the cell. When a cell is immersed into a hypertonic solution, the tendency is for water to flow out of the cell in order to balance the concentration of the solutes.

When plant cells are in a hypertonic solution, the flexible cell membrane pulls away from the rigid cell wall, but remains joined to the cell wall at points called plasmodesmata. The cell takes on the appearance of a pincushion, and the plasmodesmata almost cease to function because they become constricted: a condition known as plasmolysis. In plant cells the terms isotonic, hypotonic and hypertonic cannot strictly be used accurately because the pressure exerted by the cell wall significantly affects the osmotic equilibrium point.

A hypertonic solution is used in osmotherapy to treat cerebral hemorrhage.^{[citation needed]}

Hypotonicity[edit]

Hypotonic refers to a lesser concentration. In biology, a hypotonic solution has a lower concentration of solutes outside the cell than inside the cell. In an attempt to balance the concentrations of solutes inside and outside the cell, water will rush into the cell, causing it to swell and possibly burst.^[2]

Some organisms have evolved intricate methods of circumventing hypotonicity. For example, saltwater is hypertonic to the fish that live in it. They need a large surface area in their gills in contact with seawater for gas exchange, thus they lose water osmotically to the sea from gill cells. They respond to the loss by drinking large amounts of saltwater, and actively excreting the excess salt. This process is called osmoregulation.

Isotonicity[edit]

An isotonic solution is one in which its effective osmole concentration is the same as the solute concentration of a cell. In this case the cell neither swells nor shrinks because there is no concentration gradient for water across the cell membrane. Water molecules diffuse through the plasma membrane in both directions, and as the rate of water diffusion is the same in each direction that cell will neither gain nor lose water. An iso-osmolar solution can be hypotonic if the solute is able to penetrate the cell membrane. For example an iso-osmolar urea solution is hypotonic to red blood cells causing their lysis. This is due to urea entering the cell down its concentration gradient followed by water. For example, the osmolarity of Normal saline, 9 grams NaCl dissolved in water to a total volume of one litre, is a close approximation to the osmolarity of NaCl in blood, i.e. Normal saline is almost isotonic to blood plasma. Both sodium and chloride ions cannot freely pass through the plasma membrane as opposed to urea.

References[edit]

^ Sperelakis, Nicholas (2011). Cell Physiology Source Book: Essentials of Membrane Biophysics. Academic Press. p. 288. ISBN 978-0-12-387738-3.
^ "Definition — hypotonic". The Free Dictionary. Retrieved 23 August 2012.

UpToDate Contents

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1. 水分バランス異常（低ナトリウム血症および高ナトリウム血症）およびナトリウムバランス異常（循環血液量減少および浮腫）の一般原則 general principles of disorders of water balance hyponatremia and hypernatremia and sodium balance hypovolemia and edema
2. 成人における維持輸液療法および補充輸液療法 maintenance and replacement fluid therapy in adults
3. 小児における高ナトリウム血症 hypernatremia in children
4. 小児における低ナトリウム血症 hyponatremia in children
5. 緊張性瞳孔 tonic pupil

English Journal

Effect of Poria cocos on hypertonic stress-induced water channel expression and apoptosis in renal collecting duct cells.

Lee SM, Lee YJ, Yoon JJ, Kang DG, Lee HS.SourceDepartment of Oriental Medicine and Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan 570-749, Republic of Korea; Hanbang Body-fluid Research Center, Wonkwang University, Iksan 570-749, Republic of Korea.
Journal of ethnopharmacology.J Ethnopharmacol.2012 May 7;141(1):368-76. Epub 2012 Mar 6.
ETHNOPHARMACOLOGICAL RELEVANCE: A major physiological role of the kidney is to regulate body water and urine concentration. Aquaporin-2 (AQP2), a family of water channels, plays an important role in the urinary concentrating process and regulation of water balance in the kidney. The dried sclerotia
PMID 22414475

Tonicity enhancer binding protein (TonEBP) and hypoxia-inducible factor (HIF) coordinate heat shock protein 70 (Hsp70) expression in hypoxic nucleus pulposus cells: Role of Hsp70 in HIF-1α degradation.

Gogate SS, Fujita N, Skubutyte R, Shapiro IM, Risbud MV.SourceDepartment of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Jefferson Medical College, Philadelphia, PA, USA.
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.J Bone Miner Res.2012 May;27(5):1106-17. doi: 10.1002/jbmr.1571.
The objective of our study was to examine the regulation of hypoxic expression of heat shock protein 70 (Hsp70) in nucleus pulposus cells and to determine if Hsp70 promoted hypoxia-inducible factor (HIF)-1α degradation. Rat nucleus pulposus cells were maintained in culture in either 21% or 1% oxyge
PMID 22322648

Japanese Journal

非母語話者による英語音調核の音声的実現と非母語話者間の理解度の関係(<特集>英語教育のなかの音声)

家村雅子
音声研究 15(1), 73-86, 2011-04-30
… 本論文は,英語イントネーションの構成領域の内,tonicity(主調子配置)の重要性を指摘するJenkins(2000)提案による異なる母語(L1)をもつ非母語話者(NNS)間の効果的なコミュニケーションのための(特に音韻面の)共通項であるLingua Franca Core(LFC)への問題意識を出発点とする。 …
NAID 110008712319

落語の談話的構造 : 「間」と「音調」

角岡賢一
龍谷大学国際センター研究年報 20, 47-60, 2011-03
… In this framework, the intonation system includes Tonicity and tone. … Tonicity is related to the placement of pause,and the tone is the height of the voice pitch of the speaker. …
NAID 110008738939