Acid/Base balance Flashcards
What ratio does blood pH depend on?
It depends on the ratio of carbonic acid to bicarbonate ions
How do you measure pH?
-log10 (H+)
What does increased metabolism in the body do to the pH?
pH decreases as there is increased Co2/ increased carbonic acid
How does the body deal with the changes in the pH?
Buffering systems
Bicarbonate (major buffering system)
Phosphate
Haemoglobin
Plasma and cell protein
How does the renal system balance pH?
Reabsorbing filtered HcO3-
Producing new HCO3-
and tubular secretion of H+
Where does bicarbonate reabsorption occur?
80% at the PCT
20% in the loop of henle
How does bicarbonate reabsorption occur?
H2O and Co2 are absorbed into the cell from the lumen they then combine to form H2Co3, Which splits into HCO3– this is then aborsbed into the blood
How is HCO3- reabsorbed from the interstitial space into the peritubular capillaries
Na+/ HCO3- transporters (in the proximal tubules)
Cl-/ HCO3- exchangers (in the collecting tubules)
How does synthesis of new bicarbonate occur?
In the tubular cell H20 splits into H+ and O2, the H+ then combines with Co2 which is a product of cellular metabolism to form new HCO3-
What are three ways H+ can be secreted in the kidney tubules?
Electrogenic H+ pump
Na/H+ exchanger
H+/K+ exchanger
What is the name of the cells that are used to pump HCO3- from the tubular cell into the tubular lumen
Type B intercalated cells
What is acidosis?
an abnormal process that produces acidaemia/ low pH
What is respiratory acidosis?
low pH where the primary defect is an increase inn Co2
What is metabolic acidosis?
low pH where the primary effect is an increase in plasma HCO3-
What is alkalosis?
abnormal process that produces alkalaemia (high pH)
