Kidney function 5

Question 1

What is normal plasma value for the arterial partial pressure of CO2

Answer 1

5.3 kPa

Question 2

What is normal plasma value for arterial/venous [HCO3-]

Answer 2

25mM

Question 3

What is plasma pH proportional to? What controls them

Answer 3

pH == [HCO3-]/[pCO2]

hco3 dealt with in kidneys, co2 by lungs

Question 4

Describe the physiology of the renal H+ excretion

Answer 4

H2CO3 dissociates into H+ and HCO3-

The H+ diffuses out into lumen and joins with HPO42- and is excreted, HCO3- diffuses into blood

Question 5

What enzyme produces H2CO3 from H20 and CO2

Answer 5

Carbonic anydrase

Question 6

How does the kidney add HCO3- to plasma via glutamine

Answer 6

Glutamine brought into cell via Na+ cotransport, it is metabolised into NH4+ and HCO3-

Ammonium secreted and HCO3- added to blood

Question 7

Describe pCO2 and [HCO3-] in resp. alkalosis

Answer 7

Low CO2, no change

Question 8

Describe pCO2 and [HCO3-] in resp. acidosis

Answer 8

High CO2, no change

Question 9

Describe pCO2 and [HCO3-] in non resp acidosis

Answer 9

no change in CO2, bicarbonate low

Question 10

Describe pCO2 and [HCO3-] in non resp alkalosis

Answer 10

no change in CO2, bicarbonate high

Question 11

What is a normal value for pCO2 in arteries

Answer 11

5.3kPa

Question 12

What is a normal arterial [HCO3-]

Answer 12

25 mM

Question 13

What is a normal arterial [HCO3-]

Answer 13

25 mM

Question 14

At what pH do proteins (His residues) ionise

Answer 14

~6

Question 15

At what pH does ammonia ionise

Answer 15

9.2

Question 16

At what pH does phosphate ionise

Answer 16

6.8

Question 17

At what pH does bicarbonate ionise

Answer 17

6.1

Question 18

At what pH does urate ionise

Answer 18

5.8

Question 19

At what pH does citrate ionise

Answer 19

5.5

Question 20

What is the usual range for pH of urine

Answer 20

4.4-8

Question 21

Where does bicarbonate reabsorption occur

Answer 21

Prox tubule
Asc loop of henle
Cortical collecting ducts
(intercalated cells type A)

Question 22

What transporter is involved in NH4+ secretion

Answer 22

Na+:NH4+ exchanger

Question 23

What is metabolic alkalosis caused by

Answer 23

repeated vomiting
excess aldosterone
excess alkali ingestion

Question 24

What is pendrin

Answer 24

Found in type B intercalated cells of collecting duct

Excretes HCO3-

Question 25

What does the liver do in response to acidosis

Answer 25

increased glutamine production

Question 26

What does the liver do in response to alkalosis

Answer 26

decreased glutamine production