Carbon Dioxide in Blood

Question 1

How is CO2 transported in the blood?

Answer 1

60% HCO3-
30% carbamino compounds
10% dissolved

Question 2

What is the total content of CO2 in arterial blood?

Answer 2

21 mmol/L

Question 3

What is the solubility factor of CO2?

Answer 3

0.23

Question 4

What is the effect of CO2 in the plasma?

Answer 4

Controls pH

CO2 + H2O H2CO3 H+ + HCO3-

Question 5

What happens to the pH if pCO2 rises?

Answer 5

pH becomes more acidic

Question 6

What happens to the pH if pCO2 falls?

Answer 6

pH becomes more alkaline

Question 7

What is the Henderson-Hasselbalch equation?

Answer 7

Way of calculating pH from pCO2 and [HCO3-]

pH = 6.1 + log([HCO3-}/(pCO2*0.23))

Question 8

How is the pH of arterial blood determined?

Answer 8

Ratio of pCO2 and [HCO-]

Question 9

How is HCO3- produced in RBCs?

Answer 9

CO2 + H2O H+ + HCO3-

H+ binds with Hb-

Chloride-bicarbonate exchanger transports HCO3- out of cell

Question 10

What is carbonic anhydrase?

Answer 10

Enzyme that speeds up

CO2 + H2O H+ + HCO3-

Question 11

What is the effect of H+ binding to Hb?

Answer 11

The amount of HCO3- produces by RBCs depends on the binding of H+ to Hb

Question 12

What is the role of the kidney in controlling [HCO3-]?

Answer 12

Varies excretion of HCO3-

Question 13

What affects H+ binding to Hb?

Answer 13

More oxygen binds to Hb - R state = less H+ binding

Less oxygen binds to HB - T state = more H+ binding

Question 14

What happens to venous blood at the lungs?

Answer 14

Hb picks up O2 - less affinity for H+

H+ binds with HCO3- to form CO2

CO2 breathed out

Question 15

How are carbamino compounds formed?

Answer 15

CO2 binds to amine groups on Hb