acid-base review and aspirin tox Flashcards
what is the range of normal pH
7.37-7.42
what are the systems that modulate fast pH correction?
breathing and chemical buffering of the ICF and ECF
what is the mechanism that occurs slowly to regulate pH
the kidneys
example of a volatile acid that is produced by the body?
CO2 produced by anaerobic respiration.
non volatile acid examples
ketoacids, lactic acids, phosphoric acid. also there is consumption of acids.
where does H+ secretion occur in the nephron?
in the proximal tubule, distal tubule and the collecting duct.
how is the secreted acid in the nephron buffered?
mainly y phosphates
what happens to the water of metabolism and the CO2?
they re combined to form bicarb. a single proton is secreted and bicarb ion is kept and transferred outside the cell to buffer.
what is the pH of the tubular fluid when it is at its minimum?
4.4
where is ammonium secreted?
in the proximal tubule and the collecting duct.
what is diffusion trapping and how does that apply to the nephron and ammonia?
in the collecting duct NH3 is freely diffusible form the interstitial fluid. there is combination of the H+ with the NH3 in the tubule forming NH4+ and thus it cannot go back across the membrane due to its charge and excreted from the kidney. this is an important mechanism during acidosis because it increases to attempt and compensate. increased glutamate metabolism is the mechanism
what happens to the NH4+ mechanism in chronic renal failure and why?
there is decreased fixed acid secretion because of a decrease in GFR and a decrease in the glutamate metabolism. dialysis is required to remove the acid of metabolism
if the [H+] and the CO2 are going the same way what kind of disorder is it?
respiratory.
what are the causes of metabolic acidosis
excessive production or ingestion of fixed acids such as ketoacids, lactic acids, salicylate. loss of bicarbonate via the kidney or the GI tract. inability to secrete fixed acids from normal metabolism (chronic renal failure)
series of acidotic compensation
gain of fixed acids decreases the ECF pH. this is rapidly buffered and decreases the bicarbonate and pH. chemoreceptors inducing ventilation to remove excess CO2. renal response occurs over days to remove NH4+ through the urine.
