L18- blood gases

Question 1

factors affecting amount of gas taken up for transport

Answer 1

• how much gas contained in a litre of blood whether it’s transported in solution or bound to carrier molecules
• amount of blood transported so CO
• modulation of gas content in blood

Question 2

what is flux or flow

Answer 2

how many litres of gas per min are transported

Question 3

formula for gas or substance dissolved

Answer 3

partial pressure x solubility coefficient (alpha)

Question 4

is O2 or CO2 more dissolved

Answer 4

CO2 even with a lower partial pressure

Question 5

types of gas carrier molecules

Answer 5

-Hb

Question 6

properties of Hb

Answer 6

• has a haem group that binds to each 02 molevcule
• carries both O2 and CO2 and buffers pH
• has aplha and beta chains and they binds to CO2 and H+
• beta chains binds to 2,3-DPG

Question 7

when the metabolic gases bind to a protein, it’s no longer in what

Answer 7

in solution so it doesnt move across the partial pressure gradient

Question 8

what happens to the HB binding with O2 as the PO2 increases

Answer 8

-more O2 bound to HB so the saturation increases producing sigmoid curve

Question 9

saturation of Hb eqn

Answer 9

(O2 bound/O2 capacity ) x 100

Question 10

why is there a sigmoid shape when Hb becomes saturated

Answer 10

• everytime O2 is bound, Hb slightly changes its shape so it’s easier for another O2 molecules to bind too
• the curve levels off because its almost saturated

Question 11

what’s P50 on Hb sigmoid graph

Answer 11

at a partial pressure of O2 where Hb is 50% saturated

-measure of affinity of Hb for O2

Question 12

increased factors that decrease affinity or PO50

Answer 12

-PCO2
[H+]
-2,3-DPG
-temperature
- the sigmoid curve will move to the right - this is the bohr’s effect
- if these factors are decreased, the affinity increases and move to the right

Question 13

explain why bohr’s effect occurs

Answer 13

-binding of C02 and H+ to the alpha and beta chains changes the shape of Hb and the affinit of haem group for O2

Question 14

why is bohr effect useful

Answer 14

• binding of CO2 and H+ helps to unload O2 to the tissues as the affinity decreases
• 02 delivery matches tissue metabolic needs

Question 15

what is 2,3-DPG

Answer 15

side product produced in glycolysis

-binds to beta chains and increases O2 delivery and decreasing co2 to the tissues in alkalosis and chromic hyproxia

Question 16

why is carbonnic anhydrase used

Answer 16

used to speed up the reaction of forming carbonic acid

-protected from degradation if present in the RBCS

Question 17

pathways where CO2 can be used in the plasma

Answer 17

1. in solution for partial pressure
2. bind to a protein as a carboxyl group
3. forms carbonic acid so HCO3 and H ions are formed too

Question 18

pathways where CO2 can be used in the RBC

Answer 18

1. in solution for partial pressure
2. bind to a deocy -Hb protein as a carboxyl group
3. forms carbonic acid so HCO3 and H ions are formed too

Question 19

how does HCO3 get transported out of the RBC to the plasma

Answer 19

through HCO3-CL-exchanger

Question 20

what stores CO2

Answer 20

HCO3

Question 21

what is haldane effect

Answer 21

• at lower O2 saturation, more CO2 can bind to be removed from the tissues
• at higher saturation, More CO2 released to the tissues

Question 22

haldane effect vs bohr effect

Answer 22

Haldane effect is what happens to pH and CO2 binding because of oxygen, and Bohr effect is what happens to oxygen binding because of CO2 and lower pH.