Acid-base balance

Question 1

What is normal PCO2?

Answer 1

40

Question 2

What is normal pH

Answer 2

7.4

Question 3

What is normal blood bicarbonate?

Answer 3

25

Question 4

an acid is an H+ _____

Answer 4

donor

Question 5

a base is a substance that can

Answer 5

bind a H+

Question 6

pH is the

Answer 6

negative logarithm of the H+ in mol/L

Question 7

What is normal blood pH?

Answer 7

7.4

Question 8

What is normal stomach pH?

Answer 8

1.5

Question 9

What is normal bile pH?

Answer 9

8

Question 10

What is normal urine pH?

Answer 10

5-8

Question 11

What effect does diet have on pH?

Answer 11

protein are metabolized to sulphuric acid

Question 12

What prevents severe acidosis when we eat meat?

Answer 12

buffers like bicarbonate, monohydrogen phosphate and ammonia

Question 13

decreasing PCO2 increasing bicarbonate =

Answer 13

increasing pH

Question 14

increasing PCO2 decreases bicarbonate =

Answer 14

decreases pH

Question 15

Why is the bicarbonate buffer system so efficient?

Answer 15

because both sides of the equilibrium can be independently regulated

Question 16

Metabolic acidosis

Answer 16

is low bicarbonate, fixed by decrease CO2

Question 17

Metabolic alkalosis

Answer 17

high bicarbonate, fixed increase in CO2

Question 18

Respiratory acidosis

Answer 18

increased CO2, fixed by increase bicarbonate

Question 19

Respiratory alkalosis

Answer 19

Decrease CO2, fixed by decrease bicarbonate

Question 20

What happens when bicarbonate buffers acid from proteins?

Answer 20

bicarbonate is changed to CO2 and H2O

Question 21

Bicarbonate is made

Answer 21

on demand by the kidneys in response to decrease blood pH, and is formed when the acid in the urine is excreted at ammonium and dihydrogen phosphate

Question 22

Urinary Buffers?

Answer 22

Ammonia and phosphate, ammonia is better because it is made on demand rather than from food

Question 23

Differences between Ammonium and Ammonia?

Answer 23

Ammonium is a weak acid.
Ammonium does not readily cross cell membranes and blood vessels.
Ammonium concentration increase in a more acid environment in collecting duct lumen and excreted in urine

Ammonia freely diffuses across cell membranes

Question 24

What is the journey of Ammonium in the nephron?

Answer 24

1. ammonium is made in proximal tubule by glutamine
2. ammonium is reasorbed in the loop of henle
3. ammonia diffuses through medulla
4. ammonium trapped by H+ secretion by CD (through ATPase proton pump)

Question 25

When is Ammonium Excretion Increased?

Answer 25

Metabolic acidosis, respiratory acidosis, higher protein intake, if there is a large acid load, ammonium excretion can increase 5-10 fold but it takes 3-5 days to reach maximum

Question 26

where is bicarbonate reabsorbed>

Answer 26

proximal tubule

Question 27

What are the three mechanisms of Metabolic Acidosis?

Answer 27

Addition of an acid not normally present
failure of the kidney to excrete ammonium
loss of sodium bicarbonate through diarrhea

Question 28

What are acids that can cause metabolic acidosis?

Answer 28

lactic acid (from anaerobic glycolysis, anemia, drugs that interfere with mitochondrial function, shock states, liver failure)
Diabetic ketoacidosis (lack of insulin, fatty acid converting to ketoacids)
Methanol poisining
Ethylene glycol poisoning
Salicylate poisoning