Water and Electrolytes

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水电酸碱失衡什么意思~

水和电解质平衡
水和电解质平衡(water and electrolytes balance)是指机体每日摄取和排出的水量及钠量(细胞外液主要的电解质)是否保持平衡和如何保持平衡。
水和钠的平衡调节
每天摄入的水和钠盐的量虽有较大的变异,但体内水和盐的含量却相对稳定,这是由于摄入量和排出量保持着动态平衡之故。成年人每天摄入食盐10.5克,排泄的总量也为10.5克(表4)。这种动态平衡的维持有赖于神经和体液的调节作用。体内水的含量与氯化钠的含量有着密切的关系,当体内氯化钠的含量增多时,水的含量也增多。相反,当体内缺氯化钠时,水的含量随之减少,严重时可导致循环衰竭,这是由于血量减少,动脉血压降低的缘故。


体内水含量的调节体内水的含量取决于水的摄入量与排出量的平衡情况,水摄入量的控制主要根据渴觉,而排出量的控制主要取决于血浆中抗利尿激素的浓度,即通过抗利尿激素来调节尿量的多少。渴觉中枢和抗利尿激素的分泌细胞位于下丘脑内,血浆晶体渗透压升高时,引起抗利尿激素分泌增加,同时可刺激渴觉中枢,引起饮水。此外,来自心血管压力感受器与容积感受器(主要位于右心房)的传入冲动,抑制抗利尿激素的分泌。当血压降低与血量减少时,使抗利尿激素分泌增加,同时醛固酮的分泌也增加,这样,引起钠水潴留,使血量增加。细胞外液量的调节主要表渗透压的调节与容积调节两方面。
①渗透压调节:细胞外液的渗透压一般维持在一定的水平。这对维持细胞的正常形态与功能是必要的。当机体失水时血浆晶体渗透压升高,刺激下丘脑内的视上核渗透压感受器与渴中枢(位于下丘脑的外侧区),引起抗利尿激素(ADH)分泌和释放增加,ADH经血液运输到达肾远曲小管与集合管上皮细胞的基底侧膜,与膜上的受体结合,在上皮细胞内产生环腺苷酸。使该上皮细胞的管腔膜对水的通透性增加,从而使水的重吸收增加,尿量减少。另一方面由于渴中枢兴奋,引起口渴,主动饮水。这样体内水含量增加,使升高了的晶体渗透压又恢复到正常的水平。相反,当体内水含量增加时,血浆晶体渗透压下隆,抗利尿激素的分泌减少,因而肾远曲小管与集合管对水的通透性下隆,水重吸收减少,尿量增多,排出体内多余的水分,于是供血浆渗透压恢复到正常水平。
体内水含量的调节示意
②容积调节:当血量发生改变时,血压随之影响低压系统(静脉)与高压系统(动脉)中的压力感受器或容积感受器。压力感受器主要位于颈动脉窦与主动脉弓,容积感受器主要位于在、右心房与肺静脉。当血量增加时,上述感受器的传入冲动增加,反射地抑制抗利尿激素与醛固酮的分泌,从而使肾小管对水与钠的重吸收减少,尿量增加,细胞外液容积减小,血量即恢复到正常水平。相反,当血量减少时,上述感受器的传入冲动减少,对抗利尿激素与醛固酮的分泌不起抑制作用,因而此两种激素分泌增加,使肾小管对水与钠的重吸收增加,引起钠、水潴留,于是使血量得以恢复(图2)。
一般情况下渗透压的调节较容积调节要敏感得多,血浆晶体渗透压只上升1.2%就可引起抗利尿激素分泌明显增加,而血量需下降8%以上才可引起抗利尿激素的明显增加。但就抗利尿激素分泌的最大值来说,血浆渗透压的作用不如容积调节的作用大。血浆晶体渗透压的最大升高,也不能使抗利尿激素分泌超过10倍,可是当血量损失25%以上时,抗利尿激素的分泌量可达20~50倍。也就是说在血量下降很大的情况下,容积调节的作用远远超过渗透压的调节作用,这时即令血浆晶体渗透压低于正常值,抗利尿激素的分泌量还是显著增加,说明在这种严重情况下,确保血量的生理意义要比确保渗透压大得多。
此外,在血浆量的调节中肾素-血管紧张素-醛固酮系统也起着重要作用。当血量减少时,肾血流减少,引起肾小球旁细胞分泌肾素。肾素使血浆中血管紧张素原转变成血管紧张素Ⅰ(AⅠ),随后继转变成血管紧张素Ⅱ(AⅡ),而AⅡ既可增加醛固酮的分泌,又可兴奋渴中枢醛固酮分泌增加,使肾小管对钠的重吸收增加;渴中枢兴奋,使饮水量增加。因此,钠水潴留使细胞外液量增加,血量得以恢复。
体内钠含量的调节水平衡的调节依赖调节饮水量(凭渴觉)与肾排水量,而排水量又与血浆钠含量密切相关。在人类钠平衡的调节则主要依赖调节肾的排钠量。肾脏的保钠能力是很强的,当机体缺钠时尿中钠明显减少甚至消失。肾脏排钠的量受到以下因素的调节。
①肾素—血管紧张素—醛固酮系统:这是保钠的主要调节系统,因为当体内缺钠时肾小球滤过液中的钠含量减少,含钠少的管腔液流过致密斑时,引起致密斑兴奋,从而使肾小球旁细胞分泌肾素进入血液,导致血管紧张素Ⅱ的浓度升高。肾上腺皮质球状带对血管紧张素Ⅱ的敏感性高,使醛固酮分泌增加,从而加强肾小管对钠的重吸收。
②脑室钠—敏感感受器:在脑室内存在钠-敏感感受器,对水盐平衡的调节起着一定的作用。向颈动脉灌注高张氯化钠溶液或提高脑脊液中钠离子的浓度,可使尿钠的排出量增加。向羊的第3脑室或侧脑室后慢滴注高张氯化钠溶液,引起饮水与抑制水利尿的效应,同时尿钠排出增多。如缓慢滴注高张蔗糖溶液却不引起上述效应,说明该感受器是感受钠,而不是感受渗透压。将高张氯化钠溶液注入到第4脑室,也可引起尿钠排出增多,但却不出现饮水与抗利尿激素分泌增多的效应。可见控制尿钠排出的钠-敏感感受器广泛分布于脑室系统,而控制水平衡的钠-敏感感受器只分布于第3脑室的前壁。因损毁羊的第3脑室前壁后,再向脑室缓慢注入高张氯化钠溶液,便不再出现饮水与抗利尿激素分泌的效应。
③排钠激素:当细胞外液量增加时,在肾脏中产生一种物质,它可抑制近曲小管对钠的重吸收,使尿钠排出量增加,因此,这物质被称为排钠激素。但对此物质的化学结构、产生的具体部位及其作用方式均不清楚,故有人对此激素的存在持怀疑态度。
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酸碱平衡
人体内各种体液必须具有适宜的酸碱度,这是维持正常生理活动的重要条件之一。组织细胞在代谢过程中不断产生酸性和碱性物质;还有一定数量的酸性和碱性物质随食特刊入体内。机体可通过一系列的调节作用,最后将多余的酸性或碱性物质排出体外,达到酸碱平衡。
酸性体质
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简介
根据科学家的研究发现,正常人血液的PH值在7.35至7.45之间,为碱性体质者,但这部分人只占总人群的10%左右,更多人的体液的PH值在7.35以下,身体处于健康和疾病之间的亚健康状态,医学上称为酸性体质者。与碱性体质者相比,酸性体质者常会感到身体疲乏、记忆力衰退、注意力不集中、腰酸腿痛、老化加快等,到医院检查又查不出什么毛病,如不注意改善,就会继续发展成疾病。当人的体液PH值低于中性7时,就会产生重大疾病,当接近5.5时,就会变成癌症患者或者植物人,如果下降到5.5以下时,人就会死亡。

危害
由于体内酸性过多而引起的病大致分为四类:
⊙强酸与钙、镁等碱性矿物质结合为盐类,即固体酸性物,造成人体骨骼中的钙离子含量降低,从而导致骨质疏松症等疾病。(原来硫酸钙,氯化钙是酸性的啊,第一次听说)
⊙强酸或酸性盐堆积在关节或器官内引起相应炎症,导致动脉硬化、肾结石、关节炎、痛风等疾病。
⊙酸性废弃物堆积,使附近的毛细血管被堵,血液循环不畅,导致糖血尿、肾炎及各种癌症。
⊙胃肠道酸性过多引起便秘、慢性腹泻、尿酸、四肢酸痛,胃酸过多导致烧心、反酸、胃溃疡等。
另外,根据调查发现,酸性体质的人罹患慢性疾病的机率很高,百分之八十五的痛风、高血压、癌症、高脂血症患者,都是酸性体质。
循环受损与内环境酸化
正常组织细胞是从微循环的血流中获得氧及各种营养物质,并且依赖于良好的微循环通路把每块组织细胞的代谢产物带入排泄器官,从体内排泄出去。
微循环是指直径小于100微米的微动脉、微静脉的血液循环。微循环血流量一方面受全身的神经,体液因素调节,如交感神经兴奋可使微循环的血流量减少,血中的去甲肾上腺素、肾上腺素及血管加压素水平增高,也可使进入微循环的微动脉收缩而致微循环血灌注减少;另一方面,微循环自身存在着反馈性调节机制,即局部组织的酸性代谢产物对毛细血管前括约肌有舒张作用。
酸性体质夺走美丽
酸性体质的人不仅身体表现虚弱,上下楼梯容易口喘粗气,而且体态易肥胖,下腹突出。最可怕的是如果不及时纠正体内的酸碱度,还会直接影响到皮肤的滋润与光滑,使人看上去憔悴无华。皮肤上容易长雀斑、痣以及皮肤变黑等。
酸性体质其它外在特征
睡眠质量不佳,多梦,疲乏,记忆力下降,脱发,体重超标,情绪不稳定,免疫力低下,易感冒等。当人体产生有此类状况时,表明身体的部分免疫细胞已休眠,而癌细胞异常活跃,产生排毒不畅和四大文明病(癌症、糖尿病、肥胖和心脑血管疾病)
你也许还很奇怪,为什么我们健康的体质会逐渐变成酸性的呢?其实这和你的不良生活方式和饮食习惯息息相关。下面就让我们来了解一下酸性体质的由来吧!要找出问题的根源,去改变你的体质,才是根本解决之道。
酸性体质从何而来
⊙熬夜会使体质变酸。晚上1:00以后不睡觉,人体的代谢作用由内分泌燃烧,用内分泌燃烧产生的毒素会很多,会使体质变酸,通常熬夜的人得慢性疾病的机率比抽烟或喝酒的人都来得高。
⊙精致食物加速体质变酸。少运动且整天坐在办公室的白领丽人最容易犯这种错误,因为吃的少,刻意选择很精致的食物而少吃粗糙的食物,这种人的肠子老化的特别快,肝功能差,大便是黑色的而且常会便秘。因为精致食物缺乏纤维素,会导致肠子功能变差,甚至萎缩,你所吃的食物变成了毒素,使你体质变酸,慢性病也开始。
⊙吃消夜的人体质容易变酸。晚上8:00再吃晚餐就算 “宵夜”了! 你是不是也常忙到 8:00 才吃饭呢?时常交际应酬的生意人,通常寿命较短,易患糖尿病、高血压。吃宵夜隔天会疲倦,爬不起床,肝也会受损,因为睡觉时,人体各器官活动力低,处于休息状态,因此食物留在肠子里会变酸、发酵、产生毒素伤害身体。
⊙不良的饮食习惯导致酸性体质。如果膳食结构不对,长期是以米、面为主食,以肉、鱼、蛋等高脂肪、高蛋白、高热量的酸性食物为主,并不注意配以蔬菜等碱性食物加以调节,经过一段时日后,就导致体液偏酸,成为酸性体质。
碱性体质
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如何拥有
酸碱平衡“食”之道
先做个小测试,你认为橘子是酸性食物还是碱性食物呢?
答案是:橘子是碱性食物。别看它味道虽然酸,但它在人体内进行分解代谢后,更增加了血液的碱性。同样的,有益于美容的醋味道也是酸的,可同样是碱性食品。蔬菜、水果中含有较多的钾盐、钠盐和有机酸,它们在人体的代谢产物内高含钙、镁、钾、钠等阳离子,所以蔬菜、水果被称为“碱性食物”。

酸碱食物列表
碱性食物: 恰玛古、蔬菜、茶叶、水果(高糖水果除外)、牛奶等。
酸性食物: 肉、蛋、鱼、动物脂肪和植物油、米饭、面食、糖类甜食等。
酸碱平衡:“饮”之道
你家里喝的是什么水?天然水?纯净水?还是电炉烧的白开水?
不管是哪种,你都可以同样做个PH值测试,看看自己平时喝的水,是否弱碱性的健康好水。
常见饮用水列表
纯净水 纯净水之所以“纯净”,是因为它最大限度地除去了水中杂质和各种人体必须的矿物元素,它的PH值一般在5.0-7.0之间,偏酸性,有的甚至比酸雨还低。长年累月喝这种水,人会越喝越老。
加了矿物质的纯水 通过在纯净水里人工添加矿物质的方法,已经被许多饮用水厂家使用。
天然水 天然水的PH值一般在7.0-8.0之间,呈弱碱性,人体长期饮用,能够维持身体保持弱碱性。各种动物实验证明,天然水可以提高小白鼠对缺氧、疲劳的耐受力,增强机体抗氧化衰老的能力。
白开水 白开水的来源是市政自来水,因当地的水质不同而有不同的PH值。建议:在水烧开后要把壶盖打开烧3分钟左右,让水中的酸性及有害物质随蒸气蒸发掉。而且烧开的水最好当天喝,不要隔夜。

1、具体含义不同
water指大范围的水域,强调物质、范围、界面。waters指的是是海水,强调来源各异、处所多样,比较正式,带有一定文学色彩。
2、用法不同
water使用较广,偏口语,还可做动词表示浇水或流口水。waters只能作为名词,偏书面化,使用较少。
例句:
I ran some hot water and washed up.
我放了一些热水把餐具洗了。
The fish are on sale from our own coastal waters.
出售的鱼来自我们自己的近海水域。



扩展资料
具体释义:
1、water
英文发音:['wɔːtə]
中文释义:
n. 水;海水;雨水;海域,大片的水
例句:Get me a glass of water.
给我一杯水。
vt. 使湿;供以水;给…浇水
例句:He went out to water the plants.
他出去给植物浇水。
vi. 加水;流泪;流口水
例句:His eyes watered from cigarette smoke.
他的眼睛被香烟烟雾呛出了泪水
2、waters
英文发音:['wɔtɚ]
中文释义:
n. 水(water的复数);海域;近海
例句:
The ship will remain outside Chinese territorial waters.
这艘船将继续停留在中国领海之外。

Water is formed by the union of tw o hydrogen atoms w ith one oxygen atom. The oxygen atom is bonded to the hydrogen atoms unsymmetrically,w ith a bond angle of 105° . This unsymmetrical arrangement gives rise to an unbalanced electrical charge that imparts a polar characteristic to the molecule. Water in the liquid state,although given the formula H2O or HOH,is composed of molecular groups w ith the HOH molecules in each group held together by hydrogen bonding. Each group or molecular cluster is estimated to have an average of 130 molecules at 0℃ ,90 molecules at 20℃ ,and 60 molecules at 72℃ . H180O90is an approximate formula for the cluster at 20℃.

Water is unusual in that the density of the solid phase,ice,is substantially low er than the density of the liquid phase,w ater. In the liquid phase the maximum density is achieved at 4℃ 。 With further cooling below this temperature there is a significant density decrease.

All chemical elements have tw o or more isotopes. In this book,how ever,w e w ill be concerned only w ith the isotopes that provide useful hydrological or geochemical information. The formula H2O is a gross simplification from the structural view point and is also a simplification from the atomic view point. Natural w ater can be a mixture of the six nuclides listed in Table 11. 1. The atomic nature of the hydrogen isotopes is illustrated in Figure 11. 1. Eighteen combinations of H—O—H are possible using these nuclides.2H216O,1H218O,3H217O are some examples of the molecules that comprise w ater,w hich in its most common form is 1H216O. Of the six isotopes of hydrogen and oxygen in Table 11. 1,five are stable and one, 3H,know n as tritium,is radioactive,w ith a half-life of 12. 43 years.

Pure w ater contains hydrogen and oxygen in ionic form as w ell as in the combined molecular form. The ions are formed by the dissociation of w ater:

w here the plus and minus signs indicate the charge on the ionic species. Hydrogen can occur in vastly different forms,as illustrated in Figure 11. 2. Although the ionic form of hydrogen in w ater is usually expressed in chemical equations as H+,it is normally in the form H3O+, w hich denotes a hydrogen core surrounded by oxygen w ith four electron-cloud pairs. In discussions of groundw ater mineral interactions,a process know n as proton transfer denotes the transfer of an H+betw een components or phases.

Table 11. 1 Natural isotopes of hydrogen,oxygen,and radioactive carbon and their relative abundance in water of the hydrologic cycle

Figure 11. 1 Isotopes of hydrogen e—electron; n—neutron; p—proton

Figure 11. 2 Four forms of hydrogen drawn to relative scale a. The hydrogen atom,a proton with one electron; b. The hydrogen molecule,two separated protons in a cloud of two electrons; c. The hydrogen core,or H+,a proton; d. The hydronium ion,oxygen with four electron cloud pairs,three of which are protonated in H3O+

Water is solvent for many salts and some types of organic matter. Water is effective in dissolving salts because it has a very high dielectric constant and because its molecules tend to combine w ith ions to form hydrated ions. The thermal agitation of ions in many materials is great enough to overcome the relatively w eak charge attraction that exists w hen surrounded by w ater,thus allow ing large numbers of ions to dissociate into aqueous solution. Stability of the ions in the aqueous solution is promoted by the formation of hydrated ions. Each positively charged ion,know n as a cation,attracts the negative ends of the polar w ater molecules and binds several molecules in a relatively stable arrangement. The number of w ater molecules attached to a cation is determined by the size of the cation. For example,the small cation Be2 + forms the hydrated ion Be ( H2O)42 +. Larger ions,such as Mg2 +or Al3 +,have hydrated forms such as Mg ( H2O )62 +and Al ( H2O )63 +. Negatively charged species,know n as anions, exhibit a much w eaker tendency for hydration. In this case the anions attract the positive ends of the polar w ater molecules. The sizes of the ions in their hydrated form are important w ith respect to many processes that occur in the groundw ater environment.

As a result of chemical and biochemical interactions betw een groundw ater and the geological materials through w hich it flow s,and to a lesser extent because of contributions from the atmosphere and surface-w ater bodies,groundw ater contains a w ide variety of dissolved inorganic chemical constituents in various concentrations. The concentration of total dissolved solids ( TDS ) in groundw ater is determined by w eighing the solid residue obtained by evaporating a measured volume of filtered sample to dryness. The solid residue almost invariably consists of inorganic constituents and very small amounts of organic matter. The TDS concentrations in groundw ater vary over many orders of magnitude. A simple but w idely used scheme for categorizing groundw ater based on TDS is presented in Table 11. 2. To put the concentration ranges in perspective,it may be useful to note that w ater containing more than 2000 - 3000 mg / L TDS is generally too salty to drink. The TDS of seaw ater is approximately 35000 mg / L.

Table 11. 2 Simple groundwater classification based on total dissolved solids

Groundw ater can be view ed as an electrolyte solution because nearly all its major and minor dissolved constituents are present in ionic form. A general indication of the total dissolved ionic constituents can be obtained by determining the capability of the w ater to conduct an applied electrical current. This property is usually reported as electrical conductance and is expressed in terms of the conductance of a cube of w ater on a side of 1 cm2. It is the reciprocal of electrical resistance and has units know n as siemens ( S ) or microsiemens ( μS ) in the SI system. In the past these units have been know n as millimhos and micromhos. The values are the same; only the designations have changed. The conductance of groundw ater ranges from several tens of microsiemens for w ater nearly as nonsaline as rain-w ater to hundredses in deep sedimentary basins.

A classification of the inorganic species that occur in groundw ater is show n in Table 11. 3. The concentration categories are only a general guide. In some groundw aters,the concentration ranges are exceeded. The major constituents in Table 11. 3 occur mainly in ionic form and are commonly referred to as the major ions ( Na+,Mg2 +,Ca2 +,Cl,HCO3,SO2 -4) . The total concentration of these six major ions normally comprises more than 90% of the total dissolved solids in the w ater,regardless of w hether the w ater is dilute or has salinity greater than seaw ater. The concentrations of the major, minor, and trace inorganic constituents in groundw ater are controlled by the availability of the elements in the soil and rock through w hich the w ater has passed,by geochemical constraints such as solubility and adsorption,by the rates ( kinetics) of geochemical processes,and by the sequence in which the water has come into contact w ith the various minerals occurring in the geologic materials along the flow paths. It is becoming increasingly common for the concentrations of the dissolved inorganic constituents to be influenced by man's activities. In some cases contributions from man-made sources can cause some of the elements listed as minor or trace constituents in Table 11. 3 to occur as contaminants at concentration levels that are orders of magnitude above the normal ranges indicated in this table.

Table 11. 3 Classification of dissolved inorganic constituents in groundwater




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