Physiological pH Buffers Flashcards
T/F: [ ] of a gas is = to the pressure of the gas
T
The [ ] of any gas in fluids will be expressed in terms of _____
pressure (P)
Borderline hemoglobin saturation to support normal brain function:
85%
More acidic pH for hemoglobin leads to…
decrease in oxygen carrying ability
Factors that influence pH:
- physical activity
- metabolism
- protein degradation
- diseases
- diseases of lungs and kidneys
- drugs
How does physical activity affect pH?
- muscles produce lactic acid which is excreted in urine
- excessive exercise can results in large amounts of lactic acid and kidneys can’t excrete it
- pH will drop
How does metabolism affect pH?
- can release acids or bases
- ex: protein degradation creates ammonia (base)
How do diseases (ex: diabetes) affect pH?
- can’t make enough insulin
- oxidize fats instead of carbs: makes acid
- not well controlled diabetes = drop in pH
How do diseases of lungs and kidneys affect pH?
- cause pH to change b/c these organs are highly involved in regulating pH
How do drugs affect pH?
- large number of drugs available to treat different types of diseases are either acidic or basic
Arrhenius theory:
- acid: release H+ when placed in water
- base: releases OH- when placed in water
Bronsted Lowry theory:
- acid: donates H+
- base: accepts H+
- reaction is reversible
- conjugate acid: comes from the base
- conjugate base: comes from the acid
Lewis theory:
- acid: accepts pair of e-
- base: donates pair of e-
pKa and pKb measures the strength of…
acids and bases
- tells us how much H+ of acid or OH- of base is released
More H+ released in solution = ______
stronger the acid
More OH- released in solution = _____
stronger the base
Ka = (formula)
[ionized form]/[unionized form]
Relationship between Ka and strength of acid:
direct relationship
pKa is the _______ of Ka
negative log
Stronger acids will have a _____ pKa
smaller
Relationship between pKa and acid strength:
inverse relationship
Buffers help keep pH of solution…
constant
pH of body:
7.4
Buffers are made up of..
weak acid and its salt (vice versa w/ base)
Def of salt:
charged compound that contains anion of acid/cation of base
- results from reaction between acid and base
Acetate buffer is an…
acidic buffer
Ammonia buffer is a…
basic buffer
Mixing of acid and base together results in…
water and base
Neutral form:
not charged
Protonated form:
has H+ attached (no charge)
Deprotonated form:
loses H+ (positive charge)
Midpoint of titration:
- max resistance range
- equal amounts of salt and acid/base
- pKa/pKb of acid/base
Why would a pH not change as much after the initial addition of a base to an acidic solution?
solution now has some salt in it, which creates a buffering system that will resist changes in pH
More salt created in a solution =
more resistance to change until there are no more of initial solution molecules left
T/F: to buffer a solution at specific pH, select acid/base whose pKa is greater than or equal to target pH
T
Henderson buffer equation for acids:
pH = pKa + log[Ac-]/[HAc]
Henderson buffer equation for bases:
pH = pKw-pKb+log[B]/[HB+]
Two ions that are in the blood that act as physiological buffers:
- carbonic acid (H2CO3)
- dihydrogen phosphate (H2PO4-)
Carbonic acid has a pKa of…
6.1
Salt of carbonic acid is…
- bicarbonate anion (HCO3-)
Dihydrogen phosphate has a pKa of…
6.7
Salt of dihydrogen phosphate is…
HPO42-
Dihydrogen phosphate loses ____ protons
3
- titration curve has 3 midpoints
T/F: [dihydrogen phosphate} is high, so it has a high buffering power in regulating pH
F, has low [dihydrogen phosphate] so it has limited buffering power
Bicarbonate ion plays a _____ important role in regulating pH than dihydrogen phosphate
more important
- more [bicarbonate]
Acidosis:
pt have blood pH less than 7.4
2 causes of acidosis:
- respiratory
- metabolic
Respiratory issues (diseases of lung/respiratory system) can cause acidosis b/c…
may not be able to efficiently eliminate CO2 from blood and will drop pH
Metabolic issues (exercise/diabetes) can cause acidosis b/c…
- release of acidic substances into blood stream from organs
Alkalosis:
pt have blood pH greater than 7.4
T/F: hyperventilation causes alkalosis
T
Vomiting, excess intake of Tums/baking soda causes…
- alkalosis
- eliminates excessive amounts of H+
Kidney disease causes alkalosis b/c…
- body can’t eliminate excessive amounts of bicarb
Alkalosis impairs…
calcium ion balance, which leads to muscle cramps and cardiac arrhythmia
