Introduction to Acid-Base

Question 1

Intro to acid base

Answer 1

DiBartola Chapter 9

Question 2

Why is CO2 considered a potential acid?

Answer 2

due to its ability to combine with H20 in the presence of carbonic anhydrase to form carbonic acid (H2CO3)

Question 3

How is CO2 removed?

Answer 3

Alveolar ventilation

Question 4

Why is acid base status important

Answer 4

gain or loss of protons
as [H+] changes results in alterations in charge and molecular configuration that may adversely affect protein structure and function. The [H+ ] of body fluids must be kept constant so that detrimental changes in enzyme function and cellular structure do not occur

Question 5

What does the law of mass action state?

Answer 5

That the velocity of a reaction is proportional to the product of the concentrations of the reactants.

Question 6

What is an indication of the strength of an acid

Answer 6

The ionization, or dissociation, constant.
Large Ka value = a lot of dissociation = strong acid
Small Ka value = little dissociation = weak acid

Question 7

What is a buffer?

Answer 7

A compound that can accept of donate protons and minimise change in pH. A buffer
solution consists of a weak acid and its conjugate salt.

Question 8

what is the isohydric principle?

Answer 8

The ability to calculate ratio of acid to salt forms in a buffer solution based on the Henderson hasselbalch equation

Question 9

What types of body buffers exist?

Answer 9

bicarbonate, which is the
primary buffer systemofECF, and nonbicarbonate buffers
(e.g., proteins and inorganic and organic phosphates)

Question 10

How much buffer can be supplied by bone

Answer 10

Bone is a prominent source of buffer and can contribute
calcium carbonate and, to a lesser extent, calcium phosphate
during chronic metabolic acidosis. Bone may even
account for up to 40% of the buffering of an acute acid load
in the dog

Question 11

Explain why the bicarbonate carbonic acid buffer is an open system and why this is important?

Answer 11

Open to breathe off CO2 and allow it to either stay at a set point OR even compensate for change which allows the equation to dramatically push to the left. Decreasing [H+]

Question 12

What is the buffering component in albumin

Answer 12

the large number of histidine (imidazole) units

Question 13

Where is inorganic phosphate an important buffer?

Answer 13

intracellularly (skeletal muscle) and in urine

Question 14

What period of time does renal compensation take

Answer 14

begins within hours, but 2-5 days to reach max efficiency

Question 15

What occurs during renal compensation?

Answer 15

increased HCO3

reabsorption and net acid excretion,

Question 16

What is the difference acidosis and acidaemia, alkalosis and alkalaemia

Answer 16

The terms acidosis and alkalosis refer to the pathophysiologic
processes that cause net accumulation of acid or
alkali in the body.
Acidaemia/Alkalaemia –> change in pH

Question 17

What two processes may result in a metabolic acidosis?

Answer 17

decreased
plasma HCO3 concentration and decreased pH
(increased [H+]) caused by either HCO3
loss or buffering of a noncarbonic (nonvolatile or fixed) acid

Question 18

What is likely to cause a metabolic alkalosis

Answer 18

usually caused by a disproportionate loss of chloride
ions from the body (i.e., loss of fluid with a chloride
concentration greater than that of ECF) or
hypoalbuminemia (because albumin is a weak acid). In the absence of volume depletion or renal dysfunction, it is extremely difficult to produce metabolic alkalosis by administration of alkali.

Question 19

What is the expected respiratory compensation for a metabolic acidosis?

Answer 19

0.7-mm Hg decrease in PCO2 for each 1.0-mEq/L decrement in plasma HCO3 concentration caused by metabolic acidosis
The page bellow this then goes on to say 1.0mmHg for 1.0 mEq/L :(

Question 20

Why are there two phases for metabolic compensation to respiratory disorders?

Answer 20

Phase One:immediate titration of predominantly intracellular nonbicarbonate buffers, resulting in an initial change in plasma HCO3-
concentration.
Phase Two; carried out by the kidneys
and results in alterations in net acid excretion
and bicarbonate reabsorption.

Question 21

What is base excess?

Answer 21

the amount
of strong acid or base required to titrate 1 L of blood to
p. 7.40 at 37 C, while PCO2 is held constant at 40 mm
Hg.

Debate continues
about whether standard bicarbonate and BE are any more
useful than bicarbonate in the evaluation of acid-base
disturbances

Question 22

What is the normal anion gap in a dog and cat?

Answer 22

Dog 12-24, cat 13-27

Question 23

What are the three independent variable involved in Stewarts Acid base

Answer 23

strong ion difference (SID), total conc of weak acid (Atot), and Pco2

Question 24

What constitutes the indpendent variable Atot (total conc of weak acids)

Answer 24

plasma proteins and phosphate

Question 25

What transporters are utilised for hydrogen excretion in the kidneys

Answer 25

2/3rds by the Na+/H+ antiporter and 1/3rd by the vacuolar H+/atpase

Question 26

Where is most bicarb reabsorbed in the kidney?

Answer 26

80% in the PCT

Question 27

What is renal bicarb resorption tightly linked to?

Answer 27

Sodium resorption and in turn chloride resorption

Question 28

What effect does hyper and hypokalaemia have on DCT reabsorption of HCO3-

Answer 28

Hyperkalemia is associated with decreased renal
HCO3-
reabsorption in the distal nephron, and hypokalemia
is associated with increased HCO3-
reabsorption.