Session 6- Acid/Base balance in the kidney Flashcards
what is the range for pH of urine
4.5 - 8.5
sensory changes of alkalaemia
numbess or tingling
muscle twitches
how does alkalaemia affect calcium
it lowers free calcium by causing Ca2+ ions to come out of solution and bind to albumin
- increases neuronal excitability
- fire action potential at slightest signal
how does acidemia affect calcium and potassium
increases free calcium by causing Ca2+ to go into solution and come off albumin
this increases plasma K concentration as [H+] increases on albumin which denatures it
-affects excitability leading to arrythmia
what contributes to Hydrogen input
diet
metabolism
what contributes to H+ output
renal
ventilation
how do kidneys alter pH
- directly by excreting or reabsorbing H+
- indirectly by changing the rate at which HCO3- is reabsorbed or excreted
How do hydrogen phosphate ions act as a titratable buffer and where
bind with hydrogen ions in the PCT allowing more hyrogen to be excreted
what is normal movement of H and HCO3-
H is normally excreted
HCO3 is normally reabsorbed
how does glutamine act as a buffer and where
it forms alpha potassium gluconate which forms 2Hco3-
2HCO3- is reabsorbed into the peritubular capillaries by cotransport with Na
it also forms 2NH4+ which forms NH3 and H+
H+ is co transported with Na+ into the lumen
NH3 freely moves into the lumen
when does metabolic acidosis occur
when dietary and metabolic input of H+ exceeds H+ excretion
lactic acidosis
ketoacidosis
renal tubular acidosis
when body loses HCO3-
Diarrhoea
what is the resposne to metabolic acidosis
respiratory compensation instant, increased ventilation, pCO2 decreases due to hyperventilation
renal compensation-Late DCT/CD secretion of H+ and potassium reabsorption of HCO3-
