Session 4- Carbon Dioxide in the Blood

Question 1

buffer equation

Answer 1

CO2 + H2O H2CO3 H+ +HCO3-

Question 2

what is the Henderson-Hassalbach equation for the bodys CO2-bicarbonate buffer system

Answer 2

pH = 6.1 + log10 ([HCO3-)/ 0.23 XPco2)

Question 3

what is the normal pH range

Answer 3

7.35 -7.45

Question 4

what is the acidic part of normal range

Answer 4

7.35.7.4

Question 5

what is teh alkalotic part of normal range

Answer 5

7.4-7.45

Question 6

in plasma what is the ratio of [HCO3-] to dissolved CO2

Answer 6

21:1

25mmol/L: 1.2mmol/L

Question 7

why is the reaction with carbin dioxide and water more rapid in rbc

Answer 7

carbonic anhydrase is present

Question 8

in what direction is the reaction drawn towards in a rbc

Answer 8

towards production of HC03- which depends primarily upon the buffering effects of Hb

Question 9

what happens to the large amounts of HCO3- produced in arbc

Answer 9

exchanged with Cl-

Question 10

what is the pH of the body fluids determined by

Answer 10

the amount of Co2 dissolved in plasma

the amount of HCO3- formed from CO2 in the rbc by a reaction involving hb

Question 11

what controls HCO3- conc

Answer 11

kidney

Question 12

what is the critical feature that is needed to maintain pH at 7.4

Answer 12

there is approximately 20 times as much Hc03- as dissolved CO2

Question 13

what is the Haldene effect

Answer 13

low o2 conc increases co2 carrying capacity of hb because release of o2 from hb promotes binding of co2

Question 14

what is the pCO2 in aterial blood

Answer 14

5.3kPa

Question 15

what is the pCO2 in venous blood

Answer 15

6kPa

Question 16

how is CO2 transported in the blood

Answer 16

10% as dissolved CO2

60% as bicarbonate

30% as carbamino compounds

Question 17

what happens to the mixed venous blood when it reaches the lungs

Answer 17

teh oxygenation of Hb makes it a less good buffer and less good at holding CO2

the H+ ions are driven off Hb react with the bicarbonate to form CO2 which is breathed out

Question 18

what does he law of mass action state

Answer 18

the rate of a chemical reaction is proportinal to the concentrations of the reacting substance

Question 19

what compensates for the acid-base disorders

Answer 19

respiratory and renal systems by altering levels of bicarbonate and pCO2

lungs are fast responders able to chnage pCO2 in seconds/minutes

kidneys start changing bicarbonate concentration within hours

Question 20

how does respiratory system compensation for metabolic acidosis occur

Answer 20

decreasing pCO2 through hyperventilation

there isnt enough bicarbonate to increase its levels to compensate for the increasing levels of CO2 so instead we lower CO2 through hyperventilation

Question 21

in metabolic alkalosis how does the resp system compensate

Answer 21

hypoventiation to increase pCo2

Question 22

issues with hypoventilation

Answer 22

our blood oxygen levels will drop