acid-base regulation week 3

Question 1

What is the physiological pH

Answer 1

7.4 or slightly alkanline

Question 2

Arrhenius Acids

Answer 2

acids increase H ions and bases increase OH ions

Question 3

Bronstead Lowry

Answer 3

acids donate protons and bases accept protons( but do not necessarily increase OH- concentration)

Question 4

Physiological sources of acid

Answer 4

• aerobic released CO2 and form carbonic acid (H2CO3) which is a weak acid
• carbonic anhydrase found on RBCs aids in speeding this rxn up.
• *Carbonic acid is a volatile acid ALL others are nonvolatile (metabolic acids)
• more CO2 =a potentially lowered pH in serum*

Question 5

Difference between acidemia and acidosis

Answer 5

Acidemia is an overabundance of H+ ions in the blood

Acidosis refers to the syndrome of conditions in the body

Question 6

What does blood pH tell you?

Answer 6

the ratio between the conjugate acid and base and NOT the amount of each

Question 7

Ways the body controls pH

Answer 7

1. Kidneys: remove H+, retains HCO3 (slow)
2. Lungs can remove CO2 (rapid)
3. Buffering: resists change in pH does not remove H+
   (instantaneous)
4. These are reversible for alkalosis

Question 8

systemic regulation of pH: lungs

Answer 8

increased H+(low pH) ions leads to increases ventilation
decreased H+(high pH) ions leads to decreased ventilation
-*remember lungs can only deal with volatile acid**

Question 9

systemic regulation of pH: kidneys

Answer 9

• produce new bicarbonate by metabolizing glutamine to make ammonium and bicarbonate
• retention of bicarbonate
• can excrete acidic or basic urine
• can act on both volatile and nonvolatile acids
• if alkaline H+ can be retained and bicarbonate excreted

Question 10

systemic regulation of pH: Buffer systems

Answer 10

• Bicarbonate: important in buffering EXTRAcellular fluid
• Phosphate: important in buffering the INTRAcellular fluid and in tubules of kidneys
• Proteins: generally neg charge and thus can absorb free H+ maintaining pH BOTH extra and intracellularly
  eg: deoxy-hemoglobin in RBCs

Question 11

what is Ka

Answer 11

the ratio of the concentration of component

pH=pKa +log[A-]/[HA]

Question 12

what happens when conj. base is equal to acid?

Answer 12

pH =pKa

Buffers are most effective when this happens

Question 13

Important concepts about buffers

Answer 13

• cannot change pH per se because they do not dispose of H+ of OH- ion
• they help resist a pH change
• Critical as a rapid acting first line of defense.

Question 14

Most important intracellular pH regulators

Answer 14

• protein buffers, phosphate buffers, and ion transporters.
• pH is slightly more acidic inside cells (pH 7.1) which corresponds with phosphate buffer system pKa allowing peak efficiency

Question 15

Respiratory acidosis

Answer 15

hypoventilation
decreased CO2 clearance
decreased serum pH
Increased renal excretion of H+ and retention of HCO3-

Question 16

Respiratory alkalosis

Answer 16

hyperventilation
increased CO2 clearance
increased serum pH
decreased renal out put of H+ and retention of HCO3-

Question 17

Systemic acidosis aka metabolic acidosis

Answer 17

abnormal loss of HCO3-
decreased serum pH
Increased ventilation to try and remove CO2
causes: diarrhea, renal problems, excessive lactic acid

Question 18

Systemic alkalosis aka metabolic alkalosis

Answer 18

abnormal retention of HCO3-
increased serum pH
Respiratory depression to retain CO2
causes: excessive vomiting, hypokalemia, mineralocorticoids

Question 19

what is a mixed acid base disorder

Answer 19

when more than one simple disturbance in acid-base exists
eg. heavy vomiting, causing loss of stomach acid and therefore a metabolic alkalosis due to too much HCO3-. However this vomiting can lead loss of blood volume, and thus an increase in lactic acid ultimately leading to metabolic acidosis.

Question 20

Salicylate poisoning

Answer 20

involves acute stimulation of the respiratory center, causing respiratory alkalosis, but also results in an accumulation of endogenous, non volatile acids resulting in metabolic acidosis.