Chem test 4 Flashcards
Buffers are solutions that contain
a weak acid and its conjugate base or a weak base and its conjugate acid.
Buffers resist change in pH when
strong acids or bases are added in limited quantity
what is buffer capacity?
Each buffer has a limit to the amount of acid/base that can be added before the buffer loses its ability to resist change
Buffers are important for a variety of chemical and biological processes that must occur in
a controlled pH range.
How is blood pH controlled?
pH regulation through the buffer system, respiratory and renal system
what are the 3 main buffer systems?
the bicarbonate, phosphate, and protein buffer systems
The respiratory system directly impacts the_______ buffer system through control of blood ______ levels
carbonic acid
CO2
The renal system is regulated by
various buffer systems and works to remove hydrogen ions through the kidneys.
what is the Henderson-Hasselbach Equation
pH = pKa + log10 ([𝐴−]/[𝐻𝐴] )
what is the equation to determine blood pH?
pH = pKa + log10 ([𝐴−]/[𝐻𝐴] ) (H-H equation)
what is one factor that can dictate the movement of acid/base drugs across a cell membrane
charge of a drug compound
Charge is controlled by what?
both the pH of the solution and the pKa of the drug
Drug absorption via passive diffusion is directly related to the
amount of ionized:unionized drug.
Understanding the physiochemical properties of the drug can help to determine if it will be able to cross a particular cell membrane (i.e. acidic drugs are better able to be absorbed in the stomach than basic drugs)
The majority of local anesthetics are
weak bases; therefore, those drugs with a pKa closer to physiological pH will exist in the more lipid-soluble unionized form. This will allow them to better cross the axonal membrane to initiate onset.
