Bronsted-Lowry theory of acids and Bases
An acid is a substance that can donate a hydrogen ion.
A base can accept a hydrogen ion
Separated only by the presence of a hydrogen ion
(e-mail me if you have more to add)
Can donate two hydrogen ions
Dissociation of an acid
The splitting apart of an acid in water to give a hydrogen ion and an anion
which is stronger an inorganic or an organic acid?
100% dissociates in water. More readily gives up a hydrogen ion
less than 100% dissociates in water. Does not give up a hydrogen ion as readily as a strong acid.
Why is the maintenance of Hydrogen Ions Important?
Optimal function of Enzymes
Proper distribution of Electrolytes ex. potassium
Optimization of myocardial contractility
Optimal saturation of hemoglobin
What does acidosis do to myocardial contractility?
Many vasoactive drugs don't work in_________
The hydrogen concentration for a PH of 7.4 is...
A convenient means of expressing hydrogen concentration
PH= -log[H+]=log 1/[H+]
K is the...........
the equilibrium constant for the dissociation of acid (HA)
carbon dioxide is a ______ acid
hydrogen ion is a ______ acid
fixed acid or nonvolatile acid
What does hydrogen ion depend on
Ratio of PCO2 and HCO3-
Carbon dioxide can be used as a measure for _____
PKA of carbonic acid is
local and immediate but incomplete
Regulate excessive changes in H+
How do the lungs buffer?
Regulate CO2 removal
act within minutes
how do kidneys buffer?
Excrete either acid or basic urine
act in hours to days
of the three buffer systems which is the most powerful?
what is the definition of a buffer
Any substance that can reversibly bind hydrogen ions
what are the components of the bicarbonate buffer
a weak acid
a bicarbonate salt
what is the pk of bicarbonate buffer system?
where does the phosphate buffer system work
renal tubular fluid
what is the pk of the phosphate buffer system
The Henderson Hasselbach equation shows us how to get PH with what values?
Need the pk
How much nonvolatile acid does the body produce each day from the metabolism of proteins?
Fluid buffers are local and immediate but incomplete T/F?
Lungs act within _________
(when referring to buffering)
kidneys are the slowest buffering system T/F?
They take hours to days, but they provide more complete correction
What does buffering capacity depend on?
Amount of buffer present
PKA of buffer
PH of the environment
Most important ECF buffer
Renal tubular buffer
Renal tubular fluid buffer
Most important ICF buffer
60-70% of buffering is ICF
what is the PKA of the bicarbonate buffer
Efficiency of bicarb buffer improve/worsens with acidosis
Body PH gets closer to the PKA of the Bicarb buffer
What is the main way kidneys control acid base balance?
By excreting acidic or basic urine
How much bicarbonate do kidneys buffer everyday
What needs to happen for kidneys to reabsorb bicarb?
it needs to react with a secreted H+
what is the pka of the phosphate buffer?
what amino acid does NH4+ get synthesized from?
for every molecule of glutamine that gets metabolized...........
2 NH+are secreted
2 Bicarb reabsorbed (which generates new bicarb)