5.4. Acid/Base Balance - Role of the Kidney Flashcards
What is the ultimate aim of the Acid/Base balance?
To protect the arterial pH
How much H+ ions enter into the system every day via the diet?
50-100mmols of H+ ions
What would the pH be, if the lungs and kidneys did not work together, due to the ingested 50-100mmols of H+ ions?
1.2-2.4
What does the buffering allow for?
Time for the kidneys to appropriately deal with the H+ ions
What is the kidney responsible for, in terms of H+ ions?
- Excretion (Elimination) of H+ ions
2. Regulation of the concentration of plasma bicarbonate
How does the kidney regulate the plasma bicarbonate?
- Reabsorbing filtered HCO3-
2. Generating new HCO£-
What is the process of bicarbonate regeneration dependent on?
Active H+ ion secretion from the tubule cells in the lumen
What are the “independent” regulatory factors determining pH?
The basics of the compensatory mechanism: pH is directly proportional to [HCO3-] / PCO2
What is responsible for the [HCO3-] in pH regulation?
pH is directly proportional to [HCO3-] / PCO2
The renal system (Renal Regulation)
What is responsible for the PCO2 in pH regulation?
pH is directly proportional to [HCO3-] / PCO2
The respiratory system (Respiratory Regulation)
What happens if there is a drop in bicarbonate concentration?
(e.g due to lactic acidosis)
There would be a decrease in pH, however the respiratory system would drop the PCO2, so the ratio will remain unafected
Where is the majority of Metabolic acid buffered?
57% buffered by bicarbonate in cells
43% buffered in the plasma
Where is the majority of respiratory acid buffered?
97% buffered in cells
