Acid/Base

Question 1

Describe the dissociation of weak acids

Answer 1

•Weak acids incompletely dissociate and the tendency of an acid to dissociate is indicated by the K_a constant.

Question 2

what is the henderson-hasselbalch equation?

Answer 2

pH = pK_a + log( [A^-]/[HA] )

Question 3

K_a = ?

Answer 3

( [H⁺][A^-] )/[HA]

Question 4

What is the major buffer system in the blood?

Answer 4

Bicarbonate

Question 5

Where do buffers work?

Answer 5

In the pH region near their pKa

(will see negligable changes in pH for addition of acids or bases)

Question 6

What is the buffering range for acetic acid? What is its pKa?

Answer 6

For example, acetic acid buffers in the range of 3.76-5.76. The pKa for acetic acid is 4.75.

Question 7

How much acid is produced by the metabolic activity of the body per day?

Answer 7

22,000 milliequivalents

Question 8

What is the blood pH normally maintained at?

Answer 8

7.35 - 7.45

Question 9

What is intracellular pH typically?

Answer 9

7.1

Question 10

What are the 4 biologic buffering systems?

Answer 10

1. Bicarbonate-carbonic acid buffer (extracellular fluid)
2. Hemoglobin buffer (RBCs)
3. Phosphate buffer (intracellular)
4. Protein buffers

Question 11

Where does reaction 2, bicarbonate hydrolyzed into CO2, occur?

Answer 11

In RBC’s mostly

Question 12

What are the major buffers inside of cells?

Answer 12

–Phosphate anions (includes organic phosphate containing anions such as glucose 6-phosphate and ATP)
–Proteins (amino acid side chains are capable of accepting H+)

Question 13

What happens if cells become overly acidic?

Answer 13

•If cells become acidic, H+ is transported out in exchange for Na+

Question 14

What happens if cells become too alkaline?

Answer 14

•If cells become too alkaline, HCO3- is transported out in exchange for Cl- (charge balance)

Question 15

Where is bicarbonate reabsorbed?

Answer 15

The kidneys

Question 16

What are the urinary acids?

Answer 16

•Urinary acids include H+, uric acid, di(tri)carboxcylic acids

Question 17

What are the urinary buffers?

Answer 17

•H2PO3- and NH4+ buffer urinary acids (pH of urine ~ 5.5)

Question 18

What are the four primary acid-base disturbances?

Answer 18

1. respiratory acidosis
2. respiratory alkalosis
3. metabolic acidosis
4. metabolic alkalosis

Question 19

What is respiratory acidosis?

Answer 19

Increase in P_aCO₂ levels.

Question 20

What is respiratory alkalosis?

Answer 20

decrease in PaCO2 levels

Question 21

What is metabolic acidosis?

Answer 21

lowered ratio of HCO3- to PCO2 due to either accumulation of acids in the blood or loss of bicarbonate

Question 22

What is metabolic alkalosis?

Answer 22

•increased ratio of HCO3- to PCO2 due to ingestion of alkalis or loss of gastric acid

Question 23

What are the five steps to approaching an Acid-base disturbance question?

Answer 23

1. Does the pH indicate an acidemia or an alkalemia?
2. Is the change in PaCO2 in the direction expected for a primary respiratory disturbance?
3. If a primary respiratory disturbance is present, is it acute or compensated?
4. If a primary metabolic disturbance is present, is an abnormal anion gap present?
5. If a primary metabolic disturbance is present, is there an appropriate respiratory system response?

Question 24

Describe acute respiratory acidosis/alkalosis

Answer 24

Respiratory changes in the absence of renal compensation

Question 25

Describe acid-base disorders of a chronic nature

Answer 25

•respiratory changes in the presence of renal compensation- takes 2-3 days for the kidneys to compensate for the initial disturbance

Question 26

Where is the primary disturbance in metabolic acidosis/alkalosis?

Answer 26

The bicarbonate concentration, respiratory compensation happens immediately.