Chapter 4 Acid-Base Disturbances 0 OH
H+ OH– H2O Chapter 4 Acid-Base Disturbances
Case study woman 38, 2-day history of weakness and postural dimness History: laxativeabuse with multiple bowel movements each day Physical examination BP110/60 mmHg falls to 80/50 mmHg HR 100 beats/min and regular Skin turgor is poor The mucous membrane is dry
woman 38 ， 2-day history of weakness and postural dizziness History：laxativeabuse with multiple bowel movements each day Physical examination： BP 110/60 mmHg falls to 80/50 mmHg HR 100 beats/min and regular Skin turgor is poor The mucous membrane is dry Case study
Laboratory test INa =140 mmol/L K=3.3 mmol/L [CH=116 mmol/L Urine [ Na=9 mmol/L bUn=40 mg/dL Arterial pH=7. 25 THCo3=12 mmol/L Paco2=28 mmHg What kind of acid-base disorder did she have?
Laboratory test： [Na+ ] = 140 mmol/L [K+ ] = 3.3 mmol/L [Cl- ] ＝ 116 mmol/L Urine [Na+ ] = 9 mmol/L BUN = 40 mg/dL Arterial pH = 7.25 [HCO3 - ] = 12 mmol/L PaCO2 = 28 mmHg What kind of acid-base disorder did she have?
Acid-base balance 单映真急 Acid-base disturbance 急 What is acid? What is base
Acid-base balance Acid-base disturbance What is Acid ? What is Base ?
Acid-base balance and its requlation 令 H
一、 Acid-base balance and its regulation H+ H+
Sources of acid and base AA Acids are ht donors Bases are H+ acceptors, or give up OH-in solution Acids and bases can be Strong -dissociate completely in solution HCL NaOh Weak - dissociate only partially in solution Lactic acid. carbonic acid
Sources of acid and base • Acids are H+ donors. • Bases are H+ acceptors, or give up OH- in solution. • Acids and bases can be: – Strong – dissociate completely in solution • HCl, NaOH – Weak – dissociate only partially in solution • Lactic acid, carbonic acid
Kinds of acid and base Volatile CO2+日2o→>H2CO Acid Fixed acid:H2SOA、H2POA、HCL Base:HCO3、Ib、Na,HPO4、NH
Volatile: Fixed acid : H2SO4、H2PO4、HCL Acid Base： HCO3 -、Hb-、Na2HPO4 、NH3 Kinds of acid and base CO2 ＋H2O H2CO3 CA
The body produces more acids than bases Acids take in with foods Acids produced by metabolism of lipids and proteins Cellular metabolism produces CO2 CO2+H20←H2CO3H+HCO3
The body produces more acids than bases • Acids take in with foods • Acids produced by metabolism of lipids and proteins • Cellular metabolism produces CO2 . • CO2 + H20 ↔ H2CO3 ↔ H+ + HCO3 -
Control of acids 1. Buffer systems Take up H+ or release H+ as conditions change Buffer pairs- weak acid and a base Exchange a strong acid or base for a weak one Results in a much smaller pH change
Control of Acids 1. Buffer systems Take up H+ or release H+ as conditions change Buffer pairs – weak acid and a base Exchange a strong acid or base for a weak one Results in a much smaller pH change
Bicarbonate buffer Sodium Bicarbonate(NaHCO3 )and carbonic acid(H2 co3) Maintain a 20: 1 ratio: HCO3: H2CO3 HCl+ NaHco Hco + NaC Naoh+ hco +> NaHco +ho
Bicarbonate buffer • Sodium Bicarbonate (NaHCO3 ) and carbonic acid (H2CO3 ) • Maintain a 20:1 ratio : HCO3 - : H2CO3 HCl + NaHCO3 ↔ H2CO3 + NaCl NaOH + H2CO3 ↔ NaHCO3 + H2O
