Lecture 2: Acid/Bases

Question 1

Bicarbonate Buffer Equation

Answer 1

CO₂ + H₂O H₂CO₃HCO_3^- + H⁺

carbon dioxide + water carbonic acid bicarbonate + hydrogen ion

Question 2

Acidosis

Answer 2

pH below blood pH

Question 3

Alkalosis

Question 4

Normal Vales to Know:

Acidic—–basic

pH:

PCO2:

HCO3:

Anion GAP:

paO_2:

O₂ saturation

Answer 4

pH: 7.35-7.45

PCO2: 45-35

HCO3: 22-26

AG: 8-16

paO₂≈85-105 mm Hg

O₂ saturation > 95%

Question 5

Anion Gap Calculation

Answer 5

= Na⁺ - (Cl⁻ +HCO₃⁻)

Question 6

What is the most predominant buffer system in the body?

Answer 6

Bicarbonate buffer system

HCO₃-/CO₂ > Hemoglobin > Plasma Proteins > Phosphate

Question 7

Normal Anion Gap Acidosis

Answer 7

USEDCARP

• Ureterostomy
• Small Bowel Fistula
• Extra Chloride
• Diarrhea
• Carbonic anhydrase inhibitor (acetazomide)
• Adrenal insufficiency
• Renal Tubular acidosis
• Pancreatic fistula

Question 8

High Anion Gap Acidosis

Answer 8

MUDPILES

• Methanol
• Uremia (Chronic renal failure)
• Diabetic ketoacidosis
• Paraldehyde
• Iron, isoniazid
• Lactic Acid
• Ethanol, ethylene glycol
• Salicylates (Aspirin poisoning)

Question 9

Hydrogen bonding activity of water

Answer 9

maxium of 4-H bonds with neighboring molecules

Question 10

H₂O moves readily across cell membranes to __________ solution.

Answer 10

more concentrated

Question 11

At pH 7.4 ratio of [HCO_3^-]/[H₂CO₃]

Answer 11

must be 20:1

Question 12

Total Blood CO_{2 =}

Answer 12

H₂CO₃ + HCO₃^- + CO_3^- (negligible)

Question 13

Relative Component Concentrations:

Answer 13

HCO_3^- > CO_2(aq) > H₂CO₃ > CO_3^-

Question 14

Major CO₂ carrier:

Answer 14

HCO₃-/CO₂ > Hemoglobin > Plasma Proteins

Question 15

Carbonic Anhydrase

Major Sites:

Functions:

Answer 15

A zinc-containing enzyme essential for H2CO3/CO2 and HCO3- transfer. Facilitates equilibration of CO2 gas with aqueous phase of blood. Each complete pass of blood requires 1 minute.

Major Sites: RBC and renal tubular epithelium

Functions: facilitates transport of CO₂ and renal recovery of HCO₃-

Question 16

Fates of Renal H⁺

Answer 16

• No net proton excretion for recovery of filtered NaHCO3
• Net proton excretion in distal tubule contributes to the titratable acidity (acid salts) of urine and NH4+ content
• Total Urine Acidity = ( Titratable acid + NH₄⁺ - HCO₃^- )

Question 17

Diuretic Drug Targets

Answer 17

Carbonic Anhydrase inhibitors

Acetazolamide

-Diamox (alkaline diuresis)

Question 18

Amino acids —-> CO2 + H2O + urea +

Answer 18

“Fixed Acids”

Question 19

Low oxygen leads to

Answer 19

increased lactic acid

Question 20

excess mobilizaton leads to

Answer 20

increased acetoacetic acid

Question 21

Major - sulfur containing amino acids:

Answer 21

Met and Cys yield SO₄^2- + 2H⁺

Question 22

Phospho-amino acids + phospholipids yield

Answer 22

HPO₄^2- + 2 H⁺

Question 23

Meat and eggs are _____ in fixed acids. Fruit and vegetables are _____ in fixed acids

Answer 23

high; lower

Question 24

Daily Acid load (70 kg person)

Volatile:

Nonvolatile or fixed:

Answer 24

15-23 moles CO₂/day

70-100 mmoles/day

Question 25

the amount of strong acid or base added to one liter (l) of the system in order to change the pH one unit

Answer 25

buffer capacity

Question 26

Buffer agents-

Intracellular:

Extracellular:

Answer 26

proteins and phosphate

bicarbonate and ammonia

Question 27

Hemoglobin represent _____% of the chemical buffering capacity of blood

Plasma proteins including phosphates represent ______% of capacity

The carbonic acid and bicarbonate system represents ______ % of the buffering capacity

Answer 27

80, 14, 6

Question 28

respiratory compensation reaches max in ______

metabolic compensation reaches max in ______

Answer 28

few hours

2-5 days