Regulation od acid/base balance Flashcards
What is pH?
A measure of the conc of protons/H+
Metabolic reactions produce an excess of what?
H+ and CO2
What is the function of buffer systems?
Act quickly to temporarily bind excess H+ or OH -, sequestering (hiding) the highly reactive ions until they can be permanently excreted
How do the lungs act to maintain acid-base balance?
Change the rate and depth of breathing
- CO2 is exhaled or retained, and blood pH is corrected
What are the limitations of respiratory system for correction of acid-base balances?
- only functions when the respiratory system and control centres are working normally
- limited by the availability of bicarbonate ions
- Cannot protect the ECF from pH changes due to increased or depressed CO2 levels
How are some proteins secreted in the PCT and LOH?
Via NH4 sodium antiporter on the apical membrane
Which two types of intercalated cells are found in the distal nephron and when do they work?
Type A (alpha) cells work during acidosis Type B (beta) cells work during alkalosis
What is the main function of alpha cells?
Synthesise and absorb brand new bicarbonate ions
What is the main function of beta cells?
Secrete HCO3- into filtrate exchange for chloride ion causing absorption of “new” H+
In the kidney what 2 substances in the filtrate act as buffers?
Ammonia and phosphate ions
When does respiratory acidosis occur?
whenever CO2 accumulates because of hypoventilation. In healthy animals CO2 never accumulates in arterial blood
When does metabolic acidosis occur?
whenever non-respiratory acids accumulate, or the acid load is normal, but bicarbonate is deficient.
What type of compensation is there for a respiratory acidosis?
Metabolic compensation
How are blood test results interpreted for an acidosis or alkalosis?
Look at pH scale first – acidosis/alkalosis
- If acidosis look at values of pCO2 and bicarbonate
