Acid Base Balance

Question 1

What are the features of a good buffer?

Answer 1

abundant and the pKa of the acid should be close to the pH you’re trying to regulate

Question 2

What is the normal pH of the body?

Answer 2

7.4

Question 3

What enzyme is required for bicarbonate to act as a buffer?

Answer 3

carbonic anhydrase

Question 4

Where is there the most carbonic anhydrase?

Answer 4

red blood cells

Question 5

What is the pK for the buffer reaction?

Answer 5

6.1

Question 6

How do you alter blood pH?

Answer 6

by altering the ratio of CO2 and HCO3-

Question 7

How do you change the concentration of CO2?

Answer 7

change ventilation

Question 8

How do you change the concentration of HCO3-?

Answer 8

change the amount of bicarbonate that is reabsorbed and secreted in the kidney

Question 9

What other buffers are present in the body apart from bicarbonate?

Answer 9

plasma proteins, phosphate, haemoglobin

Question 10

What are the normal causes of acid production in the body?

Answer 10

lactic acid from anaerobic metabolism, keto acids from breakdown of fatty acids, GI secretions

Question 11

What is the normal anion gap?

Answer 11

12mmol

Question 12

What is the normal anion gap due to?

Answer 12

plasma proteins

Question 13

When will you see a high anion gap?

Answer 13

lactic acidosis, diabetic ketoacidosis, renal failure

Question 14

How does the kidney reabsorb bicarbonate?

Answer 14

in the proximal tubule there is a sodium hydrogen exchanger which will secrete hydrogen into the lumen where it will react with the bicarbonate with carbonic anhydrase to make CO2 which can diffuse across the membrane into the cell where it reacts with the carbonic anhydrase to go back into bicarbonate and hydrogen ions. The hydrogen ions are recycled and the bicarbonate is reabsorbed via a pump.

Question 15

What will chronic vomiting lead to?

Answer 15

metabolic alkalosis

Question 16

What will chronic diarrhoea lead to?

Answer 16

metabolic acidosis

Question 17

What will chronic renal failure lead to?

Answer 17

metabolic acidosis

Question 18

What will starvation lead to?

Answer 18

metabolic acidosis (due to ketoacidosis)

Question 19

When do you see a high level of bicarbonate?

Answer 19

in metabolic alkalosis and in respiratory acidosis (as compensation)

Question 20

When do you see a low level of bicarbonate?

Answer 20

in metabolic acidosis and in respiratory alkalosis (as compensation)

Question 21

What happens to potassium in metabolic acidosis?

Answer 21

get hyperkalemia because the potassium will be drawn out of cells as H+ goes in to them and because the kidney will excrete H+ ions instead of K+ but the hyperkalemia shows an artificial elevation