17. Gas Transport

Question 1

[oxygen]alveolar= ? - ?

Answer 1

[oxygen in]lungs (100mmHg) - [oxygen used] by tissue (tissue O2 consumption)

Question 2

Since O2 has a limited solubility in water/plasma, what is the solublilty of O2?

Answer 2

0.3mL/dLblood/100mmHg

meaning if PaO2 is 100mmHg, then each dL of blood will carry 0.3 mL O2

Question 3

How many liters of blood per minute would our heart have to pump in order to meet our metabolic demands of 250mlO2/min?!?!

Answer 3

83 liters of blood per min (lol)

Question 4

What are we reffering to when we say the PaO2 in arterial blood?

Answer 4

Reffering to dissolved oxygen

Question 5

Hemoglobin is used and an equilibrium between the plasma and Hb is acheived, allowing for?

Answer 5

Us to get the rest of the O2 needed

Question 6

Hb-O2 dissociation curve: As oxygen in mmHg in arteries increases, so does the Hb saturation. What is unique about the Hb O2 dissociation curve?

Answer 6

Cooperativity. As one O2 binds to Hb, a conformational change occurs leading to a second to bind, to a third and fourth.

Question 7

At PaO2 greater than 60mmHg, the Hb is at least?

Answer 7

saturated at 85%, meaning our oxygen content is at least 20.1mlO2/dlblood (cardiac output) x .85 = 17mL/O2/dLblood meeting the metabolic demands

Question 8

What occurs during a left shift of the Hb-O2 curve of HbA?

Answer 8

A left shift increases the affinity of Hb for O2 (remember to add in amount of O2 dissolved (0.3/100mmHg) with the amount Hb accounts for)

Question 9

What does a right shift represent in the Hb-O2 curve?

Answer 9

A decrease in affinity of Hb for O2

Question 10

What changes make a right shift

Answer 10

High CO2 BOHR EFFECT
Low pH
Increased Temperature
Increased 23DPG

Question 11

What changes make a left shift?

Answer 11

Low CO2
High pH (low H+)
Decreased temp
Decreased 23DPG

Question 12

When is altering the Hb-O2 curve needed/necessary?

Answer 12

To get o2 in the Tissue

Question 13

O2 is released into the tissue from capillaries where it is used in metabolic processes to produce?

Answer 13

Heat, H20, and CO2

Question 14

Not all O2 is taken up by the tissue, as indicated by the venous PO2 being?

Answer 14

40mmHg (compared to PaO2 being near 100)

Question 15

O2 saturation of venous blood is about 75%. How do you calculate the O2 content?

Answer 15

20.1 mL/O2/dLblood x .75% = 15.2 mL/O2/dLblood

Question 16

20.1mL/O2/dL blood is WHAT?

Answer 16

The oxygen content when Hb-O2 curve is near 100%

Question 17

So the difference between artery and venous O2 content is representitive of the amount of O2 used in the tissue, which varies from tissue to tissue depending on the activity of each area. What is the average O2 used in the tissue?

Answer 17

20.1 (PaO2) - 15.2 (PvO2) = 5mLO2/dLblood! (in tissues)

Question 18

Adipose tissue removes very little O2 from blood while skeletal muscles removes much more. What can this tell you?

Answer 18

Oxygen utilization by the tissues are very different! if there is a larger difference in O2 between A and V you will know that the tissue is more active

Question 19

There is a consistent relationship of O2 consumed and CO2 produced. What is the relationship/ratio in glucose, fats/fattyacids, and a mix of both?

Answer 19

Glucose/carbs= 1:1 ratio = 1
FA/Fats: 7CO2:10O2 = 0.7
Mixed fuels: 200CO2/250O2= 0.8 (8/10) normal conditions

Question 20

What is the equation for respiratory quotient (RQ) which is the ratio between CO2 produced and O2 consumed?

Answer 20

RQ = V(dot) CO2 / V(dot) O2

Question 21

What are the three main players in carrying CO2 in the blood?

Answer 21

Dissolved CO2, Carbamino compounds, HCO3

Question 22

CO2 has a 20x greater solubility in water/plasma compared to O2. So take 0.3 x 20 to get the solubility, which is ?

Answer 22

6ml CO2/dLblood/100mmHg (we will never have 100mmHg though usually much less (venous) )

Question 23

Pco2 in venous blood is 45mmHg so that means that there will be?

Answer 23

2.7 mLCO2 dissolved in each dL of blood

Question 24

CO2 binds to Hb to form carboamino compounds, however it does not bind to the heme group, instead it binds to?

Answer 24

the amine groups of the chains

Question 25

What is the haldane shift?

Answer 25

The presence of O2 on the heme reduces the affinity of the hb chain for CO2

Question 26

How much CO2 (in mL/dLblood) is carried by Hb?

Answer 26

3ml! about 7 percent like dissolved CO2

Question 27

Bicarbonate (HCO3) is the main carrier of CO2 in the blood! What is the total percentage carried?

Answer 27

86%, 44mlof CO2, we carry more Co2 than O2 in our blood d/t kidneys

Question 28

As CO2 is moved into the RBC is combines with water via carbonic anhydrase, which reacts to form H2CO3 which is unstable and by carbonic anhydrase will further degrade into?

Answer 28

H+ and HCO3

Question 29

HCO3, bicarbonate, will not stay in the cell, if it does will not allow H2O to combine with CO2, it leaves the cell and brings in what into the cell?

Answer 29

Brings in Cl-, this is called the chloride shift

because both negatively charged

Question 30

As HCO3 is pushed out and Cl- is brought in which keeps reaction continuing. What can be seen then in venous plasma blood?

Answer 30

Chloride is low d/t being inside RBC, water also moves into cell and swells! larger volume in venous blood

Question 31

In the lungs, the CO2 that is dissolved will move from the blood to ?

Answer 31

Alveoli, CO2 and H+ will leave the proteins as dissolved CO2 moves there

Question 32

WHat occurs in the lung regarding bicarbonate when CO2 is released to alveoli?

Answer 32

Many of H+ are displaced from Hb as oxygen starts to bind, make the HCO3 that was formed back into CO2, to diffuse into the alveoli—-exhaled

Question 33

What is the volume carried in the blood regarding O2 and CO2?

Answer 33

20mLO2/dL blood

50mLCO2/dL blood

Question 34

Major form transported between O2 and CO2?

Answer 34

O2-Bound in heme in Hb

CO2 - HCO3

Question 35

Volume dissvoled between CO2 and O2?

Answer 35

0.3mLO2/dLblood

3mLCO2/dLblood

Question 36

Other forms between CO2 and O2?

Answer 36

None in O2

Carbamino Compounds for CO2