Acid Base Homeostasis Flashcards
Kassier-Bleich Equation
[H+] = 24 (PCO2)/[HCO3-]
What is the normal pH in the body?
7.4
How do you calculate pH?
-log[H+] with H+ in moles
What happens to pH when H+ increases?
pH decreases!
How much H+ do we have in our gut?
100 mM
How much H+ do we have in our plasma?
40 nanomoles
What can pH range between?
4-8
What is the Isohydric Principle?
If you change the [H+], you change every one of those acid-base pairs in your system/body.
What different proteins do you have in your body? What is the significance of these proteins?
- DNA, WOA, Carbohydrates
- You can add or subtract a charge/H+ from the protein
- -> This will change its ionization and alter the fundamental way it will behave
What does altering H+ concentration do to your proteins?
It alters their conformation, can change their charge and will make them overall less functional
What is Le Chatelier’s Principle?
“Equilibrium Law” - Any system at equilibrium, when disturbed, will adjust itself to (partially) counteract the disruption. == It re-establishes a new equilibrium
What is Acidemia/Alkalemia?
An increase or decrease in H+ ions representing a change in pH. Tells nothing about cause.
What is Acidosis/Alkalosis?
Description, either metabolic or respiratory, of the process that leads to the acidemia or alkalemia
What is a buffer?
-We have a huge capacity to buffer our pH using our bicarbonate levels
System seen many times:
CO2 + H2O H2CO3 H+ + HCO3-
What controls the buffering equation?
Carbonic anhydrase (bicarb equation)
What are the physiologic consequences of Acidosis?
- Inc. respiration (to blow off CO2)
- Kussmaul breathing: Deep, slow labored breaths
- Depresses cardiac contractility (below pH 7.2)
- Increases circulating catecholamine levels
- Stimulates protein catabolism, leading to negative nitrogen balance
- Leads to bone loss (removal of HCO3- for buffering)
What are the physiologic consequences of Alkalosis?
- Hypoventilation
- Cardiac arrhythmias (particularly above a pH of 7.5)
- Shifts oxygen dissociation curve to the LEFT, thereby decreasing oxygen delivery to tissues
- Increased lactate production
What are Respiratory issues derived from?
Respiratory problems!
How are respiratory issues compensated?
By the kidney
-It does this slowly over a period of days
What are Metabolic issues derived from?
Non-respiratory issues
diarrhea, RTA
How are metabolic issues compensated?
Lungs compensate –> they do this in minutes
What is loss of bicarbonate equivalent to?
Addition of acid
