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1、,第三章 水、电解质代谢紊乱,主讲人 病理生理教研室 李永渝,Disorders of Water and Electrolyte Metabolism,一、体液的分布（Distribution of body fluid：water，crystalloids、colloids） （占体重%）,成人（男） 儿童 新生儿 老年人 TBF(total body fluid) 60 65 80 52 Intracellular fluid 40 40 35 27 Extracellular fluid 20 25 45 25 Interstitial fluid 15 20 40 20 Plasma
2、 5 5 5 5,ICF(24L),ECF(12L),Male(60%)Female(55%) Most concentrated in skeletal muscle TBF=0.6BW ICF=0.4BW ECF=0.2BW,影响体液量的因素：年龄、性别、胖瘦,5,- organ (tissue) water content - fat 25%30% muscle 76% bone 14%46% liver 70% skin 72% -,1.Who is having higher proportion of body weight as fluid (water)? And Why? 1
3、. Males or Females 2.Lean or Obese 3.Young or Elderly,Quiz:,2.A fatty person and a thin person with the same body weight lost the same volume of body fluid, whose condition is worse? 3. For a fatty person and a thin person with the same body weight, who is more sensitive when water is shortage?,二、体液
4、的电解质组成（Composition of electrolyte in body fluids） Compartmental concentration (mEq/L) Plasma Interstitial fluid Intracellular fluid Positive ion Na+ 142 140 10 (Cations) K + 5 5 150 Ca2+ 5 5 0.0001 Mg2+ 3 3 40 Total 155 153 200 Negative ion Cl 103 112 3 (Anions) HCO3 27 28 10 HPO42 2 4 142 SO42 1 2
5、5 Protein(Pr ) 16 1 40 Others 6 6 Total 155 153 200,Osmotic pressure in the body fluid:,Osmotic pressure of a solution depends on the amount of osmotic effective particles.,Water moves from areas of low osmolatity to areas of high osmolatity. Osmotic pressure of ECF is roughly equivalent to ICF.,Nor
6、mal plasma osmotic pressure is 280 310 mOsm/L or mmol/L. Plasma osmotic pressure contains colloid osmotic pressure and crystal osmotic pressure.,Tonicity,四、人体水、钠的生理功能及其代谢调节（function and balance of water and sodium）,1. Water daily balance,2、水的生理功能（function of water )： water is a good solvent for many
7、 body chemicals; water is essential to metabolism; water is necessary for body temperature regulation and body fluid osmotic pressure regulation, etc., Metabolism : 食物提供：Na 24g/ 24h，肾排出量：3g/24h， 粪便排出 10mg/24h。 肾排钠特点：“多吃多排，少吃少排，不吃不排”。,3、钠的含量与分布（Content & distribution of body sodium ) Content of sodiu
8、m ：58mmol/kg，Total body sodium：6080g/ 60kg. Distribution of body sodium ：,维持细胞的兴奋性和传导性； 维持细胞外液渗透压，并影响水在细胞内、外的分布； 参与酸碱平衡的调节。,4、钠的生理功能,(Functions of sodium in body):,5、水、钠平衡的调节(Regulation of water-salt metabolism) （1） 刺激因素 血浆容量的改变：心房、大静脉 循环压力的改变：颈动脉、心房、肾脏 血浆晶体渗透压的改变：下丘脑视上核 （2）机体反应 口渴中枢兴奋 抗利尿激素 醛固酮 心房肽
9、,ECF osmotic pressure ,BV,1) Water balance is regulated by antidiuretic hormone (ADH) and the perception of thirst.,A. ADH,Hypothalamus,Thirst,B. Thirst center,BV,2) Sodium balance is regulated by aldosterone.,第二节 水、钠代谢紊乱 （unbalance of water and sodium ),Hypotonic Hypertonic Isotonic,一、分类,（二）根据血钠浓度和
10、体液容量来分,3、正常血钠性水紊乱：血清钠浓度130150mmol/L,分类表：,二、低容量性低钠血症低渗性脱水 （Hypotonic dehydration） 1.Concept 失钠多于失水，血清钠浓度130mmol/L，血浆渗透压280mmol/L，伴有ECF的减少。 The salt loss is in excess of water loss, serum Na+ is less than 130 mmol/L, and plasma osmotic pressure is less than 280 mmol/L.,2Causes and mechanism 主要是等渗性或高渗性
11、体液的丢失。 （1）肾外性原因 消化液大量丢失（Water and sodium loss through GI tract) 体液大量在体腔内积聚(Collection of the fluid in peritoneal cavity) 大量出汗（而只补充水）（Water and sodium loss through the skin),3病理生理变化（对机体影响）（Effects on body） 代偿调节变化： 体液分布异常：其他:,盐的丢失 水丢失,ECF渗透压,不渴,ADH Ald,a. 不喝水,b. 水的排泄,A. 代偿调节:,ECF渗透压 ECF 体积,ICF,c. ECF水
12、,水从ECF to ICF,细胞肿胀,B. 临床表现,d. CNS 功障,b. 肾功障,c. 组织脱水,ECF ,血容量,a. 循环功障*,盐的丢失 水丢失,ECF渗透压,脱水征（signs of dehydration）: 皮肤弹性下降，眼窝下陷；婴幼儿出现“三凹”体征。 manifested by decreased skin turgor, sunken eye socket and fontanels- because of obvious decrease of ECF.,Mainly ECF; signs of dehydration; circulatory failure ea
13、sily occur at early stage.,病生要点：,治疗原则: （1）治疗原发病，去除病因； （2）补液：补含钠液为主！,0.9%NaCl: Na=154 CL=154 Osm=308 pH=6.5,33,ECF,ICF,Treatment of hypotonic dehydration :,What happens ?,三、高渗性脱水低容量性高钠血症 （Hypertonic dehydration） 1. Concept 失水多于失钠，血清钠浓度150mmol/L,血浆渗透压310 mmol/L，伴有ECF的减少。 The water loss is in excess of salt loss, serum Na+ is more than 150 mmol/L, and plasma osmotic pressure is more than 310 mmol/L.,丧失低渗体液： 肺失水； 皮肤失水； 肾失水（中枢性、肾性尿崩症）。 渗透性利尿; 胃肠道丧失等渗或低渗液；,2Causes and mechanism 机体失水或丢失低渗体液是引起高渗性脱水的主要原因。,3病理生理变化（对机体影响）（Effects on body） 代偿调节变化： 体液分布异常：其他:,
