Acid Base- Muster Flashcards
Define Isohydric Principle
when there is a change in the [H+] concentration, it affects ALL acid-base pairs in the ENTRIE system.
What is the primary buffering system in the human body? What are the three less influential buffering systems?
Primary = bicarb (via carbonic anhydrase) Others = Hgb, bone, Phosphorus
Define Le Chatelier’s Principle
Any system at equilibrium, when disturbed, will adjust itself to (partially) counter-act the disruption.
In other words - reestablish equilibirum
Does ionization USUALLY increase or decrease function?
Decrease!
Define Acidemia/alkalemia
is an increase or decrease in H+ ion representing a change in pH. Tells NOTHING about cause
Define acidosis/alkalosis
= The description, either metabolic or respiratory of the process that leads to the acidemia or alkalemia
What is normal pH?
7.4
What is the Kassier-Bleich equation?
[H+] = (24*pCO2)/[HCO3-]
What are some physiological consequences of Acidosis?
Increased respiration Kussmaul breathing Depresses cardiac contractility Increases circulationg catecholamine levels Stimulates protein catabolism Leads to bone loss
What are some physiological consequences of alkalosis?
Hypoventilation
Cardia arrhythmias
Shifts oxygen dissociation curve to the LEFT, decreasing oxygen delivery to tissues
Increased lactate production
What are the two primary mechanisms for managing acid load?
Buffering (bicarb equation)
Renal Excretion
What are the two things kidneys MUST do to manage acid?
- Reclaim all bicarbonate
2. excrete the acid excess
Ionization INCREASES the efficiency of what three things?
Carbonic Anhydrase
Na-H pump (lumenal membrane)
Glutamine uptake
What 4 things will increase the action of the Na-H pump on the luminal side of proximal tubule cell?
Increased AGII
Increased sympathetics
Decreased pH
Increased CO2
What are two ways H+ is able to leave the proximal tubule cell into the lumen?
The Na+/H+ pump & as NH4+ in the NH4+/Na+ pump
What can glutamine be split into by glutaminase in the proximal tubule?
NH4+ and 2 HCO3-
NH4+ goes to lumen, Bicarbonate gets reabsorbed
Would B intercalated or alpha intercalated cells be more useful for ALKALEMIA?
B-intercalated! It pumps HCO3- INTO the lumen for excretion
alpha-intercalated cells cause reabsorption of bicarbonate-polar opposite of B-intercalated cells!
If there are respiratory issues what organ is responsible for compensating? how long does it take?
Kidneys must compensate, does this slowly, over a period of days
If there are metabolic issues derive from non-respiratory issues what organ compensates?
The lungs! They can do this in a matter of MINUTES.
An acidosis will be caused by manipulating the Kassier-Bleich equation in what 2 ways?
Increase pCO2
Decrease Bicarbonate
An alkalosis will be caused by manipulating the Kassier-Bleich equation in what 2 ways?
Decrease pCO2
Increase bicarbonate
If not using the Kassier-Bleich equation, what easy numbers can you memorize to help you determine pH from [H+]?
40 –> 7.4
50 –> 7.3
60 –> 7.2
70 –> 7.1
How do we deal with non-volatile (non-carbonic) acids that are derived from the metabolism of proteins?
They are excreted in the kidneys
Via what transporter does bicarbonate get reabsorbed in the proximal tubule?
Na+/3HCO3- symporter
Via what transporter does Ammonium enter the lumen in the proximal tubule?
Secondary active transport NH4+/Na+ (ammonium out, sodium in)
What are the 2 ways that bicarbonate is created in the proximal tubule cells?
Via Carbonic Anhydrase
Via Glutamine
What 2 things can lower pH and therefore increase the pump activity in the proximal tubule?
Drop in bicarbonate
Increase in CO2
(Hence the 2 things that cause acidosis!)
1/3 of the Urinary H+ is buffered by what?
phosphorous
What is the cause of a respiratory acidosis?
Primary rise in pCO2 due to lack of ventilation
Metabolic acidosis can occur via what 2 ways?
- Increase in H+
2. Decrease in bicarbonate
What is lost in excess in a person with diarrhea?
Bicarbonate
What kinds of things will cause an increase in H+?
Lactate Ketones Methanol Ethylene glycol Aspirin
What do the kidneys do during a metabolic acidosis?
Try to reabsorb all bicarbonate! But this won’t be enough. Must also excrete the acid being produced!
When H+ starts do decrease due to a respiratory alkalosis, what cell type may appear? Why?
Beta-intercalated cells!
Increase bicarbonate secretion!
What does the liver do in a respiratory alkalosis?
It converts ammonium to urea, which consumes bicarbonate! So the liver helps too!
What does a metabolic alkalosis mean?
Net loss of H+ from extracellular space
What can rise drastically during a metabolic acidosis due to vomiting etc?
Bicarbonate
