Topic 6B - Alpha stat versus pH stat Flashcards
(43 cards)
Buffer systems designed to maintain
constant ratio of?
Ratio of [OH-] to [H+] (16:1) despite changes in temperature
Bicarbonate; protein; phosphate
Primary blood buffering system
responsible for this maintaining the constant ratio is?
the imidazole moiety of the amino acid histidine
Found on most blood borne proteins
HIm+ <> H+ + Im
imidazole
In blood, this dissociation accounts
for most of the changes in pH due to
changes in temperature
Alpha stat and pH stat management
ONLY affect control of?
control of the arterial PCO2 and pH
How do you correct arterial pO2?
MUST be temperature corrected
pH of the blood will ______ with changes in temperature
vary inversely
Within body, temperature and pH ____
from organ to organ
will vary
Acid-Base balancing system does? (3)
- Maintains constant pH difference across cell membranes
- Maintains constant ratio of negative to positive charges on proteins
- Allows enzyme systems to work at optimal level regardless of temperature
pH-stat is what?
- maintain constant pH with change in temperature
- CO2 content has to increase as temperature decreases and has to decrease as temperature increases
pH-stat
— ratio changes ?
ratio of unprotonated histidine imidazole group to H+ (alpha value) changes as CO2 content increases
Alpha stat
- maintain constant CO2 content with change in temperature
- pH will increase as temperature decreases and pH will decrease as temperature increased
Alpha stat
— ratio changes how?
ratio of unprotonated histidine imidazole group to H+ (alpha value) remains constant
Alpha stat pH will increase as ___
pH will increase as temperature decreases
maintain constant CO2 content with change in temperature
Alpha stat
-maintain constant pH with change in temperature
pH stat
ratio of unprotonated histidine imidazole group to H+ (alpha value) remains constant
Alpha stat
ratio of unprotonated histidine imidazole group to H+ (alpha value) changes as CO2 content increases
pH stat
pH stat Consequences during hypothermia (5)
- blood more acidic
- hydrogen ion gradient across the cell membrane changes
- acidity alters metabolic activity
- cells do not maintain electroneutrality
- added CO2 influences blood flow regulation
pH stat – as temp decrease how do you maintain “normal” pH
as temperature decreases, CO2 is added to maintain “normal” pH
pH stat – as temp increases how do you maintain “normal” pH
as temperature increases, CO2 must be removed
Alpha Stat - as temperature decreases, pH _?
as temperature decreases, pH will rise
Alpha Stat - as temperature increases, pH will?
as temperature increases, pH will fall
Alpha Stat - Consequences during hypothermia
- maintain constant charge on alpha-imidazole side chain
- hydrogen ion gradient across cell does not change
- cellular enzyme functions are maintained
- cells maintain electroneutrality
- auto-regulation of blood flow maintained
maintain constant total CO2 content in the blood
Alpha stat
