7 Carbon Dioxide in Blood Flashcards Preview

3 Respiratory Unit > 7 Carbon Dioxide in Blood > Flashcards

Flashcards in 7 Carbon Dioxide in Blood Deck (14)
Loading flashcards...
1

In plasma, CO2 may facilitate the formation of hydrogen ions and hydrogen carbonate ions. Why is this reaction slow?

Little carbonic anhydrase in plasma

 

2

What is the dissolved concentration of COin plasma at a pCO​of 5.3kPa?

1.2mmol/L

3

How is the hydrogen carbonate which is present in blood plasma formed?

In Red blood cells

reaction with CO2

Requires carbonic anhydrase

 

4

What happens to the pH if:

pCO2 rises

[HCO3-] rises

5

Write out the Henderson- Hasselbach equation.

6

Why is it important that In plasma the ratio of [HCO3-] to dissolved COstays consistent?

[HCO3-] : CO2

20:1

As long as this ratio stays consistent, pH will be 7.4

7

What happens to the hydrogen ions which are formed from the reaction of CO2 with H2O in the presence of carbonic anhydrase? What does this cause?

Hydrogen ions bind to haemoglobin

Result: reaction drawn towards production of HCO3-

(Amount of CO2 produced largely depends on buffering capacity of haemoglobin, only minor effect due to change in pCO2)

8

How is the HCO3- exported from the red cell?

Exported in exchange for Cl-

Chloride bicarbonate exchanger

9

Name an organ in the body which has control over [HCO3-].

Kidney

10

List all the forms in which carbon dioxide is carried in the blood:

(Carbamino compounds- formed by reaction of carbon dioxide with protein part of haemoglobin)

11

Why is haemoglobin a 'better buffer' in venous blood?

Haemoglobin less saturated with oxygen

12

What % of CO2 is transported in the blood in the form of: 

  • Dissolved CO2
  • Hydrogen carbonate
  • Carbaamino compounds

13

Why is it that hyperventilation reduces the COcontent in the blood but has little effect on the oxygen concentration?

Relationship with pCO2 and CO2 is not sigmoidal. = almost linear (see graphs) 

 

14

How much carbon dioxide is taken from tissues and given off (ie transported)? What function does the rest of the carbon dioxide in the blood serve?

8% transported

Other CO2 acts as buffering system