Acid Base Imbalance Flashcards
pH
–power or potential of hydrogen
–scale that identifies the acidity or basicity of a solution
–hydrogen ion concentration
increase in hydrogen ions equals…
more acidic pH (lower)
decrease in hydrogen ions equals…
more basic pH (higher)
what can acids do with hydrogen ions?
donate them
what can bases do with hydrogen ions?
–accept them
–give up hydroxide ion (OH-)
what do strong acids do in solutions?
dissociate
what do weak acids do in solutions?
dissociate partially
what does hydrogen do in the body?
–helps maintain cell membranes
–helps with enzyme activity
–component of H2O and keeps the body hydrated
–helps in energy production
what is hydrogen a component of?
–sugars
–proteins
–starch
–fats
what is a neutral pH?
7.0 (equal H+ and OH-)
pH normal range in the body
7.35-7.45
where is the most acidic place in the body?
stomach
how is the stomach equipped to handle a lower pH?
–produces mucus and bicarb to protect stomach lining from HCl
–duodenum has defense mechanisms to neutralize the acid
–LES prevents the movement of gastric acid into the esophagus
pH in skeletal muscle
6.9-7.2
pH in bone
7.4
pH in liver
7.2
pH in pleural fluid
7.6
what electrolytes are affected by the acid-base balance?
Na+, K+, Cl-
what else can be affected by the acid base balance?
–hormones
–oxygen transport and delivery
how is oxygen transport and delivery affected by acid base balance?
–more acid = Hgb will give up O2 more readily at the tissues
–more alkalotic = Hgb will hold on to O2
**prefer the body to be more acidic than alkalotic for oxygenation purposes
pH levels incompatible with life
pH < 6.8 OR pH > 7.8
two types of acids in the body
–volatile acid
–non-volatile acid
volatile acids
–can be converted to gas
–excreted/eliminated by the lungs
carbonic acid (H2CO3)
non-volatile acids
–lactic acid
–phosphoric acid
–sulfuric acid
–acetoacetic acid
–beta-hydroxybutyric
**eliminated by the kidney
phosphoric acid
works with calcium in bone
sulfuric acid
protein metabolism
acetoacetic acid
liver
beta-hydroxybutyric
diagnosis of DKA
what non-volatile acid is not excreted by the kidneys?
lactic acid
lactic acid
–metabolized by the body – primarily liver and kidneys
–can be utilized for energy production
how do acids get into the body?
–ingest in food/drink
–metabolism of lipids and proteins
–cellular metabolism waste product
buffers
chemicals in the body that combine with acid or base to change the pH
buffer specifics
–accept or release a H+
–almost instantaneous
–short-lived
3 main buffer systems
–bicarb (carbonic acid buffer)
–phosphate
–protein (hemoglobin)
bicarb location
ECF
bicarb
–CO2 byproduct of cellular metabolism
–combines with H2O in serum to form carbonic acid
–carbonic anhydrase breaks down carbonic acid
carbonic anhydrase location
many tissues of the body especially in lungs and kidneys
how is carbonic acid formed in lungs?
CO2 + H2O
how is carbonic acid formed in the kidneys?
H+ + HCO3-
phosphate buffer
–main intracellular buffer
–H+ + HPO4 = H2PO4-
–hydrogen + hydrogen phosphate = dihydrogen phosphate ion
protein buffers
–nearly all proteins can function as buffers
–hemoglobin picks up CO2 at the cellular level
how do proteins work as buffers?
carboxyl group (COOH) is a weak acid that gives up H+
–amino acid
–acetic acid
amino group (NH2-) accept H+
–amino acids have both a carboxyl and amino group
–ammonia NH3
what particles are involved in cellular compensation?
H+ –> positively charged ions
K+ –> positively charged ion, mostly found inside cell
what happens when there is an increase in H+ concentration?
–pH decreases = more acidic
–H+ move into the cell
–more positively charged ions in the cell
–K+ moves out of cell
–electrical neutrality is restored inside cell
effect on K+ when pH becomes more acidic
increased K+ in the blood –> hyperkalemia
cellular compensation
–temporary correction of pH
–process will reverse as pH returns to normal
–if kidneys are working, they will excrete the excess K+ = hypokalemia
respiratory mechanisms in acid base balance
–body produce CO2
–CO2 and H2O creates carbonic acid
–exhalation excretes carbonic acid
–doesn’t affect fixed acids (non volatile) like lactic acid
–converts volatile acids to gas
–body pH can be adjusted by changing rate and depth of breathing
RR in acidotic patients
increased RR to blow off CO2
RR in alkalotic patients
decreased RR to retain CO2
kidney excretion role in acid base balance
–can eliminate large amounts of acid except carbonic acid
–can also excrete base
–can conserve and produce bicarb ions
–most effective regulator of pH
–if kidneys fail, pH balance fails
–depends on normal functioning of renal system
rates of correction for mechanisms
–buffers almost instantaneously
–respiratory = several minutes to hours
–renal = several hours to days
compensation
body response to acid-base imbalance
respiratory compensation
if underlying problem is metabolic, hyperventilation or hypoventilation can help
metabolic compensation
if problem is respiratory, renal mechanisms can help
process for correcting acidosis
acidosis –> stimulates brain and arterial receptors –> increase RR –> decrease blood CO2 –> decrease carbonic acid –> increased pH
process for correcting alkalosis
alkalosis –> stimulates brain and arterial receptors –> decrease RR –> increase blood CO2 –> increase carbonic acid –> decrease pH
what is the primary controller of the body’s carbonic acid supply?
lungs
what does CO2 mix with to form carbonic acid in the lungs?
H2O
hyperventilation
blows off CO2 and increases pH
hypoventilation
retains CO2 and decreases pH
renal response time for correcting pH
hours to days
what are the primary controllers of bicarb in the body?
kidneys
how do kidneys control pH?
by adjusting amount of bicarb that is…
(1) reabsorbed into the bloodstream
(2) excreted in the urine
how will kidneys respond if blood is too acidic?
reabsorb bicarb
how will kidneys respond if blood is too alkalotic?
excrete bicarb
normal range for CO2
35-45
normal range for HCO3
22-26
