Acid Base Balance Flashcards
Hemoglobin is a_____________ buffer that binds H+ on __________________
Protein; histidine (imidazole) or carboxyl groups
In the late DT and Cd, Type A cells secrete __________ and type B cells secrete _________
Acid; bicarbonate
What two organs help maintain physiological pH?
Lungs and kidneys
What is the dissociation constant for bicarbonate buffer?
PKa= 6.1
What are the three buffer systems?
Bicarbonate
Phosphate
Proteins
What are the intracellular buffers?
Amino acids, protein, phosphate
A condition cause by the addition of excess acid or removal of base from the ECF
Acidosis
An elevation of pH above the normal range
Alkalemia
A molecule that can release(donate) H+ ions
Acid
A pH > 7.4 is a with low levels of pCO2 is a _______________ which requires what type of compensation?
Respiratory alkalosis; renal compensation (decrease HCO3-)
What is the most important extracellular buffer?
Bicarbonate
What common disorders cause respiratory acidosis?
Alveolar hypoventilation
Fractured ribs
Bloated abdomens
Respiratory obstructive disease
What three systems regulate pH in the body?
Buffer
Respiration
Kidney
What buffers are important in interstitial fluid?
Bicarbonate, phosphate, protein
Type A cells have H+ ATPase and H+/K+ ATPase located __________, and an HCO3-/Cl antiporter located ________?
Apically; basolaterally
Type B cells are flipped
How does an increase in ventilation change pH?
Increase ventilation -> CO2 elimination -> decrease H+ concentration -> increase pH
If H+ excretion > HCO3- excretion the urine is _______
Acidic
How does an intercalated cells change its morphology in response to and acid-base imbalance ?
Cell actively secreting protons -> increase carriers and SA on apical membrane
Fewer vesicles seen -> fused with he apical membrane
An pH <7.4 with elevated pCO2 is a _____________________ that requires what type of compensation?
Respiratory acidosis; renal compensation (increase HCO3-)
Increasing altitude has what affect on physiological pH and how is it compensated?
Low pO2 at high altitude -> increase ventilation and exhaled CO2 -> decreased pCO2 =>respiratory alkalosis
Compensate by renal excretion of HCO3-
Where is HCO3- reabsorbed in the kidney?
PT, TAL, DT and CD
How does acid-base balance alter K+ concentration?
H+ elimination is accompanied by K+ reabsorption
acidosis -> high H+ eliminated -> increased K+ reabsorption -> hyperkalemia
Alkalosis -> H+ reabsorbed -> K+ secreted -> hypokalemia
How does the phosphate buffer maintain pH?
HPO4 combines with H+ (base) to increase pH
Eg HCl + HPO4 -> H2PO4 + Cl-
What is pH?
Measure of the proton concentration in a solution
pH and H+ concentration is inversely related
What carriers are involved in H+ secretion in the PT, TAL, and DT? Is it located apically or basolaterally?
Na/H+ antiport
H+ ATPase
Apical
A condition caused by the addition of excess base or the removal of acid from the ECF
Alkalosis
An increase in PCO2 will ____________ pH
Decrease -> acidosis
If the concentration of H+ increases, how does the bicarbonate buffer compensate?
excess H+ combines with HCO3 -> H2CO3 -> increase CO2
Excess CO2 is eliminated with he lungs
What carriers are required for HCO3- reabsorption? And where are these carriers located?
HCO3/Na cotransporter
HCO3/Cl antiporter
Basolateral membrane
A base that binds rapidly and strongly with H+ and removes it from solution
Strong base
How do proteins buffer pH and where are they important?
Important buffers in both intracellular and extracellular compartments
Contains large number of basic amino acids that bind H+
During acidosis, how does the kidney compensate to maintain pH?
High H+ concentration promotes complete reabsorption of HCO3- and the excess H+ will be eliminated in urine
A pH <7.4 with decreased HCO3- levels is a ________________ that requires what type of compensation?
Metabolic acidosis; respiratory compensation (decrease CO2)
The phosphate buffer is important (extracellularly/intracellularly)?
Intracellular
How does a decrease in ventilation change pH?
Decrease ventilation -> CO2 accumulation in body-> increase H+ -> decrease pH
What disorders lead to metabolic alkalosis?
Vomiting - loss of HCl
Torsion of abomasum- HCl trapped; reduce acid in the rest of body
Hypokalemia
Hypoparathyroidism
A substance in the body that helps maintain physiological pH (abut 7.4)
Buffer
Most acids and bases present in the ECF behave as (strong/weak) acids and bases
Weak
An acid that is generated by a hydration reaction (eg carbonic acid) is called?
Volatile acid
H2O + CO2 -> H2CO3
An acid that rapidly dissociates and releases high amounts of H+
Strong acid
What is the anion gap?
Difference between unmeasured cations and unmeasured anions
[Na+] - [HCO3- + Cl-] = (range 8-16mEq/L)
A pH >7.4 with high HCO3- levels is a __________________ that requires what kind of compensation?
Metabolic alkalosis; respiratory compensation (increase CO2)
What four parameters are required for analyzing acid-base balance status?
.pH of blood
.pCO2
Standard bicarbonate
Base excess
A molecule formed by the combination of one or more of the alkaline metals with a basic ion (OH-)
Alkali
base=alkali
What common disorders cause respiratory alkalosis?
Alveolar hyperventilation during anesthesia
High altitude
Damage to respiratory centers
Emotional excitement
An increase in HCO3- concentration will __________ pH
Increase -> alkalosis
If the concentration of H+/HCO3- decreases, how does the bicarbonate buffer system compensate?
H2CO3 dissociates to form more H+ and HCO3-
CO2 and H2O hydrolysis to form H2CO3
CO2 levels decrease and respiration is decreased
What common disorders leads to metabolic acidosis ?
Renal failure Hyperkalemia Hyperparathyroidism Diarrhea (eliminating HCO3) Fistula Mineralization of bone (requires HCO3) Lactate formation (acid formation) Satarvation Diabetes mellitus (acid ketone bodies) Increased fat mobilization Protein rich diet Rumen acidosis
What is the normal range of pH?
7.35- 7.45
A depression of pH below the normal range is ________
Acidemia
What buffer system is important in CSF?
Bicarbonate
If unmeasured anions rise or if unmeasured cations fall what happens to the anion gap?
Anion gap increased
In alkalosis, how does the kidney aid in maintaining pH?
Excess HCO3 cannot combine with H+ and is not reabsorbed -> excreted in the urine
What makes bicarbonate the most important buffer system?
Open system -modify CO2 (lungs) or HCO3- (kidney)
Abundant
Most H+ in the tubular lumen is excreted as?
Ammonia
H+ is secreted in what parts of they kidney?
PT, TAL, DT, and CD
What is the Henderson Hasselbach equation?
.pH=pKa+ log[base]/[acid]
.pH= pKa+ log [HCO3-]/[0.003 x pCO2]
Acids that are generated as by products of metabolism are called ?
Non-volatile acids
What are the important buffer systems in plasma?
Bicarbonate, protein, phosphate
An impaired lung function can cause ____________ because of the accumulation of CO2 in the body
Acidosis
