Acid Base Regulation

Acid Base Regulation

1. Blood pH maintained by H+, normal blood pH=7.35-7.45

   • Most H+ comes from metabolis, High protein diet gives some
   • pH=-Log*[H+]
   • Disorders affecting circulator buffers, renal function and respiratory performance affect acid base balance
     • ashma,emphysema, renal failure,diarrhoea
     • renal excretion of [H+] (renal compensation). Lung excretion of co2 (Respiratory Compensation)

2. Change in ph in body can affect protein shape and function

   • also pH change affects cell function and be threatening
   • Many buffers bind to H+ to increase pH, cell proteins, cell albumin and hameoglobin
     • Bicarbonate and carbonic acid do the job in plasma.
       • Phosphate in cytosol
         • H+ + Hpo4^2 <->H2po4-
           • H2p04- + OH- <->H20 + Hpo4^2-
       • Hco3- + H+ <-> H2co3<-> H2o + c02

3. xhaling co2= Rapid co2 loss, reduce carbonic acid, raise blood pH

   • Renal excretion of H+= H+ out of body slowly, Renal tubules secrete H+ into urine, Urine pH can be more conc than blood

4. 4 types of acid base imbalances, metabolic Acidosis and alkalosis and respiratory Acidosis and alkalosis

   • Blood ph below 7.35=acidosis, Depresses CNS leading to coma
     • Blood pH above 7.35= Alkalosis exciteable CNS, nervousness, pain, muscle spasms

5. An anion gap can alter due to changes in hco3-

   • Anion gap= [K+]+[NA+]-[Cl-]-[HCo3-]
   • normal range is 10-20mm/l

6. Respiratory acidosis, common form is high Pco2(>45mmHg) and low pH <7.35

   • caused by impaired gas exchange, not remove enough co2. Hypoventilation can be caused by lung diseases(asthma etc), damage to medulla, airway obstruction or respiratory muscles problem
   • ix by renal compensation but the co2 is high, increased excretion of H+ adn reabsorption of hco3( >24mm)
   • Treatment for high pCo2(hypercapnia)= increase breathing rate

7. Respiratory Alkalosis, uncommon, low pco2 <35mmHg and high pH 7.45

   • caused by Hyperventilation due to fever, anxiety, high altitude, stroke, liver diesease, drugs, poisons
   • Renal composition but low Pco2, decreased H+ excretion and HCO3-absorption. <24mm
     • treatment (Hypocapnia) low PCO2 decrease breathing rate/ breathe in bag

8. Metabolic acidosis, common, low arterial HCO3-<22mmol and low pH <7.35

   • caused by acid accumulation, due to exercise, hypoxia, starvation, diabetic ketoacidosis (lipid metabolism), diarrhoea, methanol
   • Respiratory compensation but Hco3- low, hyperventilation to increase loss of co2 (<40mmHg)
     • treat by intravenous hco3- and anion gap increases due to loss of hco3-, Ketoacidosis is uncontrolled

9. Metabolic alkalosis, uncommon, high arteriol hco3-, caused by loss of acid due to

   • vomitting, gastric suctioning, diuretics, eating aspirin overdose
     • Respiratory compensation but HCO3- high, Hypoventilation to decrease loss of co2 (>40mmHg) treatment= Ammnium chloride metabolised to HCL. Fluid to correct the K+ and cl- levels

10. If Acid base balance changed by other reasons than respiratory system and renal then both these systems work to bring back to normal

    • if deviation respiratory fault, then renal system restores it. and if deviation because of renal only respiratory system can sort this

11. 50mmol of acid in urine

    • Bone has mineral crystallites that are freed by protons and theses ions/crystallites are excreted in urine and lose CA leading to slow dissolution of bone