6.1 Acid-base Balance

Question 1

What is the range of healthy plasma pH?

Answer 1

7.35 to 7.45

Question 2

What is it called when pH drops below 7.35?

Answer 2

Acidaemia

Question 3

What is it called when pH rises above 7.45?

Answer 3

Alkalaemia

Question 4

What symptoms are felt in alkalaemia?

Answer 4

Paraesthesia- Ca2+ release

Question 5

What symptoms are felt in acidaemia?

Answer 5

Arythmyias- K+ release

Denatured proteins

Question 6

How is pH determined in the plasma?

Answer 6

Ratio of pCO2 and [HCO3-]

Question 7

What equation is used to work out pH of the plasma?

Answer 7

Hasselbach’s equation

Question 8

What is Hasselbach’s equation?

Answer 8

pH= pK + log( [HCO3-] /pCO2 x 0.23)

Question 9

What is respiratory acidosis?

Answer 9

Hypoventilation leads to a build up of CO2 which lowers the pH of the blood

Question 10

What is respiratory alkalosis?

Answer 10

Hyperventilation leads to a loss of CO2 and therefore the pH increases

Question 11

What do central chemoreceptors detect?

Answer 11

Detect changes in pO2

Question 12

What do peripheral chemoreceptor detect?

Answer 12

Detect changes in pCO2 and plasma pH

Question 13

How are changes in pCO2 compensated for?

Answer 13

Kidney can reabsorb or excrete HCO3-

Alter breathing

Question 14

What is metabolic acidosis?

Answer 14

H+ reacts with HCO3- in the tissues to produce CO2
CO2 is removed at the lungs
[HCO3-] is lowered so pH drops

Question 15

How is metabolic acidosis compensated for?

Answer 15

Increase ventilation

Question 16

When may metabolic acidosis occur?

Answer 16

Exercise

Question 17

What is metabolic alkalosis?

Answer 17

Plasma HCO3- rises so pH rises

Question 18

When may metabolic alkalosis occur?

Answer 18

After vomitting lots

Question 19

Where is most of HCO3- reabsorption done in the kidney?

Answer 19

PCT

Question 20

How does HCO3- cross the apical membrane in the PCT?

Answer 20

Joins with H+ to become H20 and CO2. They diffuse into cell. Turns back into HCO3- when inside the cell

Question 21

How does HCO3- move across the basolateral membrane of the PCT cells?

Answer 21

Via Na-HCO3-co-transporter

Question 22

Which amino acid can be converted to HCO3-?

Answer 22

Glutamine

Question 23

What buffers the influx of H+ to the lumen as HCO3- is reabsorbed?

Answer 23

HPO4+

Question 24

How is the anion gap calculated?

Answer 24

Difference between ([Na+] and [K+]) and ([Cl-] and [HCO3-])

Question 25

What would a large anion gap suggest?

Answer 25

Metabolic acidosis

Question 26

What happens to potassium levels in metabolic acidosis?

Answer 26

Increase

Question 27

What happens to potassium levels in metabolic alkalosis?

Answer 27

Decrease