Lecture 9: Acid-Base Balance

Question 1

how does the proximal tubule respond to acidaemia

Answer 1

• secretes H+
• kickstarted by Na+ / K+ ATPase
• reabsorbs HCO3-
• by carbonic anhydrase on apical side

Question 2

how does the distal tubule respond to acidaemia

Answer 2

• secretes H+
• by Na+ / H+ ATPase on basolateral membrane
• reabsorbs HCO3-
• via Cl- / HCO3- transporter
• deaminates amino acids to create more HCO3-
• all in intercalated cells

Question 3

what can cause acidosis

Answer 3

• metabolism of lactic acid
• hypoventilation
• loss of HCO3- in diarrhoea and non-gastric fluids
• loss of HCO3- in urine

Question 4

what can cause alkalosis

Answer 4

• use of H+ in metabolism
• hypervetilation
• loss of H+ in vomit
• loss of H+ in urine