Saq 1.doc Answer

SAQ 1. Describe renal compensation in acid base balance Outline: • Introduction What is acidosis (define) Response to acidosis in general - buffering - compensation - correction Role of kidney in compensation for acidosis Restoration of [HCO3]/PaCO2 ratio • Compensatory mechanisms 1. secretion of hydrogen ions associated with HCO3- reabsorption - at proximal tubules,thick ascending limb, early distal tubules percent? low gradient, high capacity system – means? (diagram) secondary active Na/H countertransport mechanism energy derived by Na/K –ATPase (basolateral membrane) CA Ratio of H to HCO3 - late distal tubules ,collecting ducts percent? Primary active intercalated cells H-ATPase transport (diagram) Ratio of H to HCO3 High gradient low capacity system - means? H secretion in distal tubules is controlled by aldosterone Importance 2. excretion of titratable acidity define important buffer systems involved (diagram) ratio

importance 3. excretion of ammonia percent source of ammonium site of occurrence transport mechanism involved- pKa (diagram) importance  Conclusion Effectiveness Slow ; 7-10 days Correction of primary source of acidosis