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ACID-BASE BALANCE pH is a measure of H + pH = - log [H +] Importance:
Chemical reactions
![ACID-BASE BALANCE pH is a measure of H + pH = - log [H +] Importance:](http://slideplayer.com./slide/13040484/79/images/1/ACID-BASE+BALANCE+pH+is+a+measure+of+H+%2B+pH+%3D+-+log+%5BH+%2B%5D+Importance%3A.jpg "Chemical reactions.")
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Acid + Base = Salt Water (NEUTRALIZATION REACTION: HCl + NaOH NaCl + H2O)
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pH SCALE Logarithmic 1.0 to 14.0 7.0 = neutral (chemical)
7.4 = normal (biological) <7.0 (7.4) = acidic >7.0 (7.4) = alkaline (basic) body pH range = 7.35 to 7.45
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ACIDS AND BASES Acid = releases H+ = proton donor
Base = accepts H+ = proton acceptor Strong acid vs. weak acid Strong base vs. weak base
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SOURCES OF H+ Metabolic reactions Carbon dioxide Exercise acids Food
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pH MAINTENANCE Buffer systems Respiratory system Urinary system
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BUFFER SYSTEMS Buffer = substance preventing extreme fluctuations of pH Strong acids/bases to weak ones Work in buffer pairs; a base and an acid Action: BB + strong acid weak acid + salt BA + strong base weak base + water Systems: bicarbonate; phosphate; protein
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BICARBONATE BUFFERS Important in blood Buffer pair = NaHCO3/H2CO3
HCl + NaHCO3 H2CO3 + NaCl NaOH + H2CO3 NaHCO3 + H2O
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PHOSPHATE BUFFERS Important in kidney Buffer pair = Na2HPO4/NaH2PO4
HCl + Na2HPO4 NaH2PO4 + NaCl NaOH + NaH2PO4 Na2HPO4 + H2O
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PROTEIN BUFFERS Important in cells Amphoteric Side groups:
COOH acts as acid – donates H+ NH2 acts as base – accepts H + Hb can act as a buffer
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Respiratory Control of pH
Review respiratory centers of brain Review respiratory equation Review chemoreceptors It is fast acting when buffers need help Control lasts relatively short time NOT a long term solution H+ = pH = resp. equation left = ventilation Consider the opposite scenario
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Renal Control of pH Kidney slow to respond to pH changes
Responds only after persistent changes Compensates for a relatively long period NOT a solution to chronic pH problems Rids the body of H+ by tubular secretion PCT, DCT, CD Also: Reabsorption of HCO3- Regulation of PO4 -3 Production and elimination of NH3
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Summary of Kidney Action
Blood Tubule Cells Filtrate CO2 CO2+ H2O H2CO3- HCO3- + H + H + + Na2HPO4 Na+ + NaH2PO4 HCO3- + Na+ Na+ NH3 NH3 + H+ (for excess H+) NH4+
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Coupling of H+ Secretion & Reabsorption of HCO3-
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Buffers & New HCO3- p. 1008
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New HCO3- & Ammonia p. 1009
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Acidosis & Alkalosis Look at the listed values in the above order
Range Acidosis Alkalosis pH < 7.4 > 7.4 pCO2 35-45 mmHg > 45 mmHg < 35 mmHg HCO3- 22-28 mEq/L < 22 mEq/L > 28 mEq/L Look at the listed values in the above order
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Acidosis & Alkalosis Acidosis Alkalosis Respiratory Metabolic
Respiratory problems Rapid, shallow breathing Overdose Brain stem injury Hyperventilation Metabolic Diarrhea Renal disease Starvation Excess alcohol Increased ECF Vomiting Excess diuretics Excess bicarbonate Constipation Excess aldosterone
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Compensation One system helping another to alleviate an acid/base problem: An overload of the buffer system results in an increase in breathing rate; the respiratory system is compensating.
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Fluids & Electrolytes Body water content Fluid compartments:
Intracellular Extracellular Plasma Interstitial fluid
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Fluid Compartments p. 1041
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Fluid Composition Electrolytes Nonelectrolytes
Comparison of intracellular & extracellular
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Fluid Composition p. 1043 Note sodium and potassium
Note similarity of plasma & interstitial fluid except for protein p. 1043
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Fluid Movement Water follows osmotic and hydrostatic pressure gradients Intracellular Interstitial Plasma
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Fluid & Solute Movement
p. 1037
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Water Balance Input must equal output p. 1037
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Regulation of Water Intake
p. 1038
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Disorders of Water Balance
Dehydration Water loss exceeds intake; When? Diabetes Decreased volume = hypovolemic shock Water movement out of cells Hypotonic hydration (Water intoxication) Excess water Diluted ECF hyponatremia Edema
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Disorders of Water Balance
p. 1040
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Electrolyte Regulation - Sodium
p. 1043
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ADH Action p. 1039
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Water: Pressure /Volume Relationships
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Water: Pressure /Volume Relationships
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Respiratory Centers Medulla Pons
Apneustic – works to smooth transition between inspiration and expiration Pneumotaxic (pontine respiratory group) Inhibits respiratory center fine tunes rhythm Prevents overinflation
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![1. pH = - log [H + ] H + is really a proton Range is from 0 - 14 If [H + ] is high, the solution is acidic; pH < 7 If [H + ] is low, the solution.](/15/4651316/big_thumb.jpg "1. pH = - log [H + ] H + is really a proton Range is from 0 - 14 If [H + ] is high, the solution is acidic; pH < 7 If [H + ] is low, the solution.>")
