Gas Transport

Question 1

Magnitude of gas pressure directly related to?

Answer 1

of gas molecules

Question 2

Gasses always flow?

Answer 2

down partial pressure gradient

Question 3

[O2] in blood includes?

Answer 3

dissolved in plasma and bound to Hb (RBC)

Question 4

[O2] in blood units?

Answer 4

ml O2 per 100 ml blood

Question 5

Saturation of Hb denoted as?

Answer 5

S

unit is % of sites bound

Question 6

O2 in lungs diffuses where to where?

Answer 6

Alveoli to blood

along gradient

Question 7

What % of O2 is carried by RBCs?

Answer 7

> 98%

Question 8

Qty of Dissolved O2 directly proportional to?

Answer 8

Po2

Question 9

Solubility of O2 is (aka solubility co-efficient)?

Answer 9

0.003 ml/ 100 ml blood/ mmHg

Question 10

Dissolved O2 =

Answer 10

0.003 x Po2

Ѧ 1.5% of O2 in blood is dissolved

Question 11

Hb can bind what molecules?

Answer 11

O2
CO2
H+

Question 12

Bound O2 does not contribute to?

Answer 12

Po2

Question 13

Degree of Hb saturation is proportional to?

But not what?

Answer 13

Po2

not linearly related

Question 14

Hb is 100% saturated at what Po2?

Answer 14

> 100 mmHg

Question 15

So2 reaches 90% when?

Answer 15

Po2 = 60 mmHg

Question 16

What happens to ∆S/∆P b/w a Po2 of 60 - 100 mmHg?

Answer 16

very little change

Question 17

At a Po2 below 60 mmHg, small ∆s in Po2 cause?

Answer 17

large ∆s in S

Question 18

O2 loading happens where?

At what pressure?

Answer 18

lungs

PalveolarO2 = 100

Question 19

O2 unloading happens where?

At what pressure?

Answer 19

tissues

Ptiss = 40

Question 20

P50 is?

Answer 20

Po2 @ 50% saturation

Question 21

At lungs:

Po2?
Hb saturation?
O2 vol in blood?

Answer 21

100 mmHg

100% saturation

20% vol of blood

Question 22

At tissues:

Po2?
Hb saturation?
O2 vol in blood?

Answer 22

40 mmHg

75% saturation

15% vol of blood

Question 23

Eqn for Calculation of [O2]

Answer 23

Find CaO2 for bound oxygen:

Hb x 1.34 x saturation

Question 24

Effects of metabolism on O2-Hb dissociation,

aka, Bohr Effect on Hb saturation curve?

Answer 24

At tissues:
↑ temp
↑ Pco2
↑ [H+] (↓ pH)
Ѧ P50↑ = ↓ affinity for O2 -> unloading O2 at tissues

At lungs:
reverse happens

Question 25

Effect of 2,3 DPG on Hb sat curve?

Answer 25

also shifts curve R at tissues

does NOT reverse at lungs

Question 26

Hypoxia is?

Answer 26

O2 insufficiency at cellular level

Question 27

Hypoxic hypoxia is?

Answer 27

Pao2, Sao2, Cao2 all ↓

e.g. high altitudes

Question 28

Anemic hypoxia (or CO poisoning)is?

Answer 28

↓ carrying capacity ->
Cao2 ↓
Pao2, Sao2 normal

Question 29

Circulatory hypoxia?

Answer 29

↓ oxygenated blood reaching tissues

e.g. HF, shock

Question 30

Histotoxic hypoxia?

Answer 30

O2 delivery normal,
tissue can’t use O2
e.g. cyanide

Question 31

CO2 carried in what forms? (3)

Answer 31

1) dissolved CO2 10% this way
2) bound to protein (carbamino) 30% this way
3) chemically modified (HCO3-) 60% this way

Question 32

CO2 solubility coefficient?

Answer 32

0.03 ml CO2/ 100 ml blood / mmHg

Question 33

dissolved CO2 =

Answer 33

0.03 x Pco2

Question 34

Dissolved CO2 is directly proportional to?

Answer 34

Pco2

Question 35

HCO3- transport?

Answer 35

HCO3- forms rapidly in cells,
HCO3-/Cl- exchange sends HCO3- into blood
Cl- shift reversed at lungs

Question 36

HbCO2 transport?

Answer 36

carbamino