Acid/Base Normal/Pathophyisology Flashcards
What is a pH <7.35
Acidic
What is a pH of >7.4
Basic
what does pH=
-log 10 [H+]
What is the most acidic body fluid?
Gastric Juices
Is pancreateic fluid acidic or basic and why?
Basic- helps neutralizes chyme from stomach upon entering duodenum
How are volatile forms body acids (ex-carbonic acid H2CO3) eliminated?
CO2
How are nonvolatile body acids (ex- sulfuric pohsphoric) eliminiated?
Renal tubules
Which process is faster at getting rid of acid- lungs or kidney?
Lungs
What is lactic acid formed by?
Anaerobic respiration of glucose
What is a buffer?
Can absorb excessive H+ or OH- without significant change in pH
Work as weak acid and conjugate base
Where are buffers located?
ICF and ECF
For the bicarbonate buffer system, what is the weak acid?
H2CO3 (carbonic acid)
What is the base in the bicarbonate buffer system?
Bicarbonate (HCO3-)
As CO2 goes up or down, H2CO3….
does the same
How do lungs decrease H2CO3?
by eliminating CO2
What do kidneys do with bicarbonate?
Reabsorb or generate new
If bicarbonate decreases, what happens to pH?
pH drops
If the bicarbonate concentration goes up, what happens to pH?
pH goes up
What is compensation ?
Normal ratio
Abnormal values
What is correction?
Values return to normal, uses the same system
What is an example of protein buffering?
Hemoglobin
What is arterial blood pH <7.4
Acidemia
What is a systemic increase is [H+]
Acidosis
What is arterial blood pH >7.45?
Alkalemia
What is a systemic decrease in [H+]
Alkalosis
What is the normal Pa CO2 range?
36-44 mm Hg
What is the normal HCO3- range?
22-26 mEq/ L
As [H+] increases what happens to pH?
decrease
Why is urine acidic?
Excess hydrogen ions are shed through urine
(5.0-6.0)
Where does carbonic acid come from?
Co2
What is the pK value?
the pH where 1/2 of the buffer layer is dissociated
What is the Henderson-Hasselbalch Equation?
pH = pK + log [base]/[acid]
What type of Hb is the better buffter?
unsaturated
Where does renal buffering occur?
DCT and collecting ducts (some PCT)
When buffers in tubular fluid combine with H+, what do they combine with?
Dibasic phosphate (when combined turns into monobasic phosphate- stays in filtrate)
ammonia (become amonium ion once combined with H+ and is excreted)
Where is HPO4- filtered?
Glomerulus , some of it remains for buffering
What are the two things that are excreted by the kidneys(thereby excreting H+ ions)
Ammonium ion and monobasic phosphate
What converts H2CO3 into H+ and HCO3- in renal buffering?
Carbonic anhydrase
How is H2CO3 created?
CO2 and H2O combine
If an individual in metabolic acidosis still have a normal anion gap what must be happening?
They are losing bicarbonate, gaining chloride
Hyperchloremic metabolic acidosis
If the anion gap is elevated in an individual with metabolic acidosis- what does that mean?
Accumulation of an anion other than chloride
What are things that lead to an increased non-carbonic acids (elevated anion gap)?
Ketoacidosis
Lactic acidosis
Ingestions
What can lead to decreaesd H+ excretion?
Uremia
Distal renal tubule acidosis
What can cause bicarbonate loss (normal anion gap)?
Diarrhea
Ureterosigmoidoscopy
Renal failure
Proximal renal tubule acidosis
What type respirations are associated with metabolic acidosis?
Kussmaul respirations (very deep, very rapid respirations)
What causes metabolic alkalosis (bicarb change)?
Bicarbonate increases
Usually due to excessive loss of meatbolic acids
What causes metabolic alkalosis?
Prolonged vomiting
Gi sunctioning
Excessive intake of bicarbonate (Tums)
What happens with vomiting with depletion of ECF and chloride
Hypochloremic metabolic alkalosis
How do the kidneys make hypocholermic metabolic alkalosis worse? Why do they do this?
By increasing sodium and bicarbonate
Increase sodium because they want to maintain water concentration
Bicarb is retained to keep proper charge balance (because Cl- is being lost through vomitting)
How do you correct Hypocholermic metabolic alkalosis?
Expand ECF with NaCl solution with K+
(K+ has been depleted because it is needed to move Na back into the body)
What is Hyperaldosteronism?
sodium retention and loss of H+ and K+
There is a mild volume expansion with bicarb retention
How would your body compensate for metabolic alkalosis?
Hypoventilation
Do diuretics helps with bicarb excretion?
No- enchance Na+ K+ and Cl- excretion more than bicarb
What are common symptoms of metabolic alkalosis?
Weakness
Muscle cramps
Hyperactive reflexes
What is the pH for metabolic alkalosis?
pH >7.45
When does respiratory acidosis occur?
Ventilation is depressed, CO2 is reatined
What is hypercapnia?
An excess of CO2
With acute uncompensated respiratory acidosis what happens to pH, PCO2 and bicarb?
Decreased pH
Elevated PCO2
Normal or slightly elevated bicarbonate
Where is a chronic form of respiratory acidosis seen?
COPD - in this case renal compensation will be effective
serum bicarb and arterial PCO2 elevated- pH restored to normal
What are common symptoms or respiratory acidosis?
Headache, restlessness, blurred vision
lethargy, muscle twitches, tremors
If a person is in chronic respiratory acidosis, what will bicarb levels be?
What about acute?
Elevated
Normal with acute
What is respiratory alkalosis due to?
Alveolar hyperventilation and excessive redution of CO2 (hypocapnia)
What are symptoms of respiratory alkalosis?
Dizziness, confusion, parasthesias, convulsions, coma
Deep, rapid, respirations (tachypnea)
In respiratory alkalsosis what is arterial pH?
What about PCO2?
arterial pH >7.45
PCO2 is decreased
In acute respiratory alkalosis what do [bicarbonate] look like? What about chronic?
Acute- bicarb is normal
Chronic- bicarb is decreased
