final Flashcards
acid
releases hydrogen ion, can raise H conc.
base
combines w hydrogen ion, lower H conc.
strong acid
acids that more completely give up H ions = ionize
ex: sulfuric acid
strong base
bases that ionize more completely
ex: HCO3-
acidosis
hydrogen ion conc. increases, pH declines, acidity of blood increases
alkalosis
hydrogen ion conc. decreases, pH increases, solution becomes more basic
normal arterial pH
7.4
3 contributors to exercise induced muscle acidosis:
- production of CO2 and carbonic acid(HCO3-) in working skeletal muscles
- production of lactic acid in working muscles
- ATP breakdown in working muscles
volatile acid
ex: CO2
as gas that can be eliminated by lungs
- exercise adds a volatile acid load on body
what type of exercise presents a threat to acid-base disturbances?
high intensity
how does changes in muscle pH affect exercise performance?
- reduces muscle cell’s ability to produce ATP (inhibits enzymes involved in anaerobic and aerobic production of ATP)
- H ions compete w Ca ions for binding sites on troponin (hinders contractile process)
buffer
resists pH change:
removes H ions when H ion conc. increases
releases H ions when H ion conc. decreases
2 factors impacting buffer ability:
- intrinsic physiochemical ability
- conc. of buffer (the greater, the better)
4 major intracellular chemical buffer systems in cytosol of muscle fibers:
- bicarbonate
- phosphates
- cellular proteins ex: histidine
- histidine - dipeptides ex: carnosine
2 primary hydrogen transporters across sarcolemma:
- sodium-hydrogen exchangers (NHE)
- monocarboxlate transporters (MCTs)
NHE function
move sodium ions into muscle and h ions into interstitial space
(one for one)
2 types of MCTs: both do?
- MCT1
- MCT4
mediate cotransport of lactate and hydrogen out of muscle across sarcolemma
which type of muscle fiber has a higher intracellular buffering capacity?
fast/ type II
3 buffer systems of blood:
- proteins
- hemoglobin
- bicarbonate
which blood buffer is important during rest?
hemoglobin:
- high conc. = 6x buffering capacity of proteins
- deoxygenated = better bind to h formed when CO2 enters from tissues
most important buffer system in body
bicarbonate
- increased blood bicarbonate conc. = improved exercise performance
henderson - hasselbalch equation
describes ability of bicarbonate and carbonic acid to act as buffer system:
- pH of weak acid solution is determined by ratio of conc. of base in solution to conc. of acid
pH= = pKa + log10(Hco3-/h2co3)
ratio of bicarbonate to carbonic acid
20 to 1
important regulator of blood carbonic acid and pH:
lungs/ respiratory system