Acid-Base Regulation Flashcards
(42 cards)
pH=
pH = -log[H+]
1 numerical change in pH =
10 fold change in the concentration of H+
pH = 7 when H+ and OH- ions are…
equal
1:1 proportion
physiological pH is
7.4
slightly alkaline
acids _____ protons
bases ______ protons
acids donate protons
bases accept protons
strong acids and bases _____ in solution
completely disassociate
HCl and NaOH
weak acids ____ in solution
Donate relatively few of their H+/OH- ions
depending
on Ka (the disassociation constant)
- hight Ka = more disassociation
biological systems involve mostly ____ acids
weak acids
strong acids would be hard to buffer
biological pH fluctuations from 7.4 of ____
+/- 0.5
acidemia
too many H+ ions in the bloodstream
arterial blood pH < 7.35
Acidosis: conditions leading to acidemia
alkalemia
too low H+ ions in the bloodstream
arterial blood pH > 7.45
alkalosis: conditions leading to alkalemia
pH regulation systems
Buffers (1st line of defense, resist change in pH, does NOT remove H+)
Lungs (removed CO2, fast acting)
Kidneys (removed H+, slow acting, can retain HCO3- bicarbonate)
pKa
The pH at which the concentrations of the two components of a
buffer are equal
pKa =
pKa = -log[Ka]
Buffer Chemistry
Henderson-Hasselbalch
pH=pKa + log [A-]/[HA]
bicarbonate buffer
key buffer in the extracellular fluid
phosphate buffer
important in buffering the intracellular fluid and in kidney tubules
proteins (buffer)
have a negative charge that can absorb H+ ions to maintain pH in both extracelular matrix and ICF
histidine side chains
hemoglobin in RBCs
carbonic anhydrase
works on red blood cells to dissolve CO2 into the blood
medulla oblongate
rapidly detects an increase in systematic H+
what does faster/deeper respiration do?
blowing off more CO2
drop in H+
raise pH
what does breathing slower/lighter respiration do?
blow off less CO2
raise H+
lower pH
lungs only deal with ____ acids
volatile acid (carbonic acid/CO2)
volatility = measure of how likely substance is to vaporize
