I - Water and pH Flashcards
Body Weight: % Dry Body Weight
40%
Body Weight: % Water
60%
Body Weight: % ICF
40% (2/3 of water)
Body Weight: % ECF
20% (1/3 of water)
Body Weight: % Interstitial Fluid
15% (3/4 of ECF)
Body Weight: % Blood Plasma
5-7% (1/4 of ECF)
Which elements can water for hydrogen bonds with?
-S, -O, -N
Both an acid and a base
Amphoteric
Has both hydrophilic and hydrophobic parts
Amphipathic
Donates protons
Acid
Accepts protons
Base
pH =
-log [H+]
pOH =
-log [OH-] or 14 - pH
Normal pH of blood
7.35-7.45
pH where reaction happens optimally
pKa (50% protonated, 50% unprotonated)
Charge of acids at physiologic pH
(-) negative
Charge of bases at physiologic pH
(+) positive
Causes of HAGMA
Methanol, Uremia, Diabetic Ketoacidosis, Paraldehyde / Propylene Glycol, Isoniazid, Lactic Acidosis (sepsis, shock), Ethylene Glycol, Salicylates
pH = pKa + log [A-]/[HA] or [B]/[HB+]
Henderson-Hasselbalch Equation
For titration of amino acids, predictng shifts in the bicarbonate buffer system and predicting distribution of drugs
Henderson-Hasselbalch Equation
actual pH < pKa
Protonated
actual pH > pKa
Unprotonated
A mixture of a weak acid and its conjugate base that can resist a change in pH when protons are produced or consumed
Buffer Solution
Maximum buffering occurs at
pKa ± 1
Physiologic Buffers
bicarbonate, proteins, orthophosphate
Most important EXTRAcellular buffer
bicarbonate
Most important INTRAcellular buffer
proteins
