Xx - Respiratory Physiology Iii

Front 1

Partial Pressure = (?)

Back 1

= (Total Pressure) x (Fractional [Gas])

Front 2

OXYGEN PARTIAL PRESSURES

- in Dry, Inspired Air = (?)

Back 2

160 mmHg

( b/c pO2 = 760 mmHg x 0.21 )

Front 3

OXYGEN PARTIAL PRESSURES

- in Humidified, Tracheal Air = (?)

Back 3

150 mmHg

( b/c pO2 = (760 - 47 mmHg) x 0.21 )

Front 4

OXYGEN PARTIAL PRESSURES

- in Alveolar Air (pAO2) = ?

Back 4

100 mmHg

(is slightly more than paO2)

Front 5

OXYGEN PARTIAL PRESSURES

- in Arterial Air (paO2) = ?

Back 5

100 mmHg

(but slightly less than pAO2)

Front 6

OXYGEN PARTIAL PRESSURES

- Mixed Venous Blood = (?)

Back 6

40 mmHg

Front 7

OXYGEN PARTIAL PRESSURES

- Compare the pO2 for Alveolar air & Arterial blood.

- What process accounts for the difference?

Back 7

- Arterial pO2 (paO2) is slightly LESS (than pAO2)

- Physiologic Shunt

Front 8

OXYGEN PARTIAL PRESSURES

- What % of Cardiac Output Bypasses Pulmonary Circulation?

- This is known as?

- Why important?

Back 8

- 2%

- Physiologic Shunt

- Resulting admixture of blood causes arterial pO2 to be slightly less than alveolar air pO2.

Front 9

CO2 PARTIAL PRESSURES

- pCO2 in Humidified, Inspired air = ?

Back 9

0 mmHg

Front 10

CO2 PARTIAL PRESSURES

- pCO2 in Dry, Tracheal air = ?

Back 10

0 mmHg

Front 11

CO2 PARTIAL PRESSURES

- of Alveolar Air (pACO2) = ?

Back 11

40 mmHg

Front 12

CO2 PARTIAL PRESSURES

- of Arterial Blood (paCO2) = ?

Back 12

40 mmHg

Front 13

CO2 PARTIAL PRESSURES

- of Mixed Venous Blood = ?

Back 13

46 mmHg

Front 14

DISSOLVED GASES

- Solubility of O2 in Blood = ?

Back 14

= 0.03 mLO2 / L / mmHg

Front 15

DISSOLVED GASES

- Dissolved [O2] in blood = (Eq.)?
- Dissolved [O2] in blood = (value)?
- Units?

Back 15

= paO2 x (Solubility of O2 in blood)

= 0.3

Units = (mLO2 / 100 mL)

Front 16

GAS DIFFUSION

- Diffusion Rates for O2 & CO2 depends on what 3 things?

Back 16

- Partial Pressure difference
(across membrane)

- Surface Area (for diffusion)

- Thickness of membrane
(for diffusion)

Front 17

Gas Exchange occurs via what 2 types?

Back 17

Perfusion-Limited Gas Exchange

Diffusion-Limited Gas Exchange

Front 18

PERFUSION-LIMITED EXCHANGE

- illustrated by what gasses?

Back 18

1.) N2O (not no2)

2.) CO2

3.) O2 during NORMAL Conditions

Front 19

DIFFUSION-LIMITED EXCHANGE

- illustrated by what gasses?

Back 19

1.) CO (not co2)

2.) O2 during STRENUOUS EXERCISE

Front 20

PERFUSION-LIMITED EXCHANGE

- What happens with the Gas Equilibrium
(along pulmonary capillaries)

- What happens with the Partial Pressure of gas in Arterial Blood?

Back 20

- gas EQUILIBRIATES early along length of pulmonary capillaries

- Equals that of Alveolar Air

Front 21

DIFFUSION-LIMITED EXCHANGE

- What happens with the Gas Equilibrium
(along pulmonary capillaries)

- What happens with the Partial Pressure of gas in Arterial Blood?

Back 21

- does NOT Equilibriate along pulmonary capillary

- Partial Pressure in blood is less than alveolar air
(thus gradient is created & MAINTAINED)

Front 22

Gas PARTIAL PRESSURE DIFFERENCE (gradient) is MAINTAINED btw Alveolar air & Arterial Air in which type of gas exchange?

What does this imply about Diffusion?

Back 22

- Diffusion-Limited Gas Exchange

(in perfusion-limited exchange, the gradient is gone b/c gases will equilibriate)

- Diffusion Continues as long as Pressure gradient is maintained

Front 23

Which Gas Exchange type occurs in Diseased States?

Back 23

- Diffusion-Limited Gas Exchange

Front 24

PERFUSION-LIMITED EXCHANGE

- Gas Diffusion character

Back 24

Gas Diffusion Increases

ONLY if Blood Flow Increases

Front 25

DIFFUSION-LIMITED EXCHANGE

- Gas Diffusion character

Back 25

Gas Diffusion Continues

as long as Partial Pressure Gradient is maintained

Front 26

Gas Exchange is illustrated by O2 under what conditions for:

- Diffusion Limited Gas Exchange?

- Perfusion Limited Gas Exchange?

Back 26

- Strenuous Exercise
- Diseased States


- Normal Conditions

Front 27

Restrictive Diseases such as FIBROSIS & SILICOSIS:

- causes what effect on O2 Diffusion?

- Pathophysiology involved

Back 27

- RESTRICTS O2 Diffusion

- Thickening of Alveolar Membrane
(thus increasing the diffusion distance)

Front 28

EMPHYSEMA

- causes what effect on O2 Diffusion?

- Pathophysiology involved?

Back 28

- DECREASES O2 Diffusion

- Destruction of Alveolar unit
(so, diffusion Surface Area decreases)

Front 29

List diseases that Decreases O2 diffusion by decreasing the Surface Area for diffusion.

Back 29

- Atelectasis

- Poor Lung Compliance states

- Emphysema

Front 30

O2 Diffusion can also be impaired by a Decrease in the actual O2 Pressure Gradient, occurring in what clinical condition?

Back 30

- High Altitude

(partial pressure of O2 decreases because of decreased [O2] & presence of water vapor)

Front 31

HEMOGLOBIN

- has how many subunits?

- each subunit has what? (describe)

Back 31

- 4

- Heme-Moiety

(Iron-containing Porphyrin)

Front 32

HEMOGLOBIN

- Hemoglobin has what type of Iron?

- why is this type of iron important?

Back 32

- FerrOus (Fe2+)

- only FerrOus Iron can bind 2 oxygen

Front 33

HEMOGLOBIN

- Methemoglobin has what type of Iron?

- how is this iron different from the one in Hb?

Back 33

- Ferric iron (Fe3+)

- Ferric can NOT bind oxygen

Front 34

HEMOGLOBIN

- describe the subunits in normal adult Hb

Back 34

alpha2, beta2

Front 35

HEMOGLOBIN

- Fetal Hb has what subunits

Back 35

alpha2, gamma2

Front 36

HEMOGLOBIN

- Compare O2 affinity of Fetal Hb to Adult Hb

- what is the reason for this?

Back 36

- Fetal Hb has HIGHER O2 affinity

- b/c it binds 2,3-DPG LESS Avidly

Front 37

HEMOGLOBIN

- what property is measured at 100% saturation

Back 37

O2 Binding Capacity

Front 38

HEMOGLOBIN

- Define O2 Binding Capacity

Back 38

- MAX amount of O2 that can be bound to Hb in blood

Front 39

HEMOGLOBIN

- O2 Binding Capacity is dependent on?

Back 39

- Hb Concentration

Front 40

HEMOGLOBIN

- normal Hb Concentration (in blood)?

Back 40

15 g/dL

Front 41

HEMOGLOBIN

- CYANOSIS begins with what Hb Concentration criteria?

Back 41

DEOxygenated Hb > 5 g/dL

Front 42

1 g of Hb bind how much O2?

Back 42

1.34 mLO2

Front 43

HEMOGLOBIN

- Normally & Numerically, (@ 100% saturation), what is the O2 Binding Capacity in blood?

Back 43

approximately 20.1 mLO2/dL

(b/c normal concentration = 15 g/dL)
(b/c 1 g Hb can bind 1.34 mLO2)

Front 44

HEMOGLOBIN

- define O2 Content

- includes what O2 types?

Back 44

- total amount of O2 carried in blood

- bound O2 & dissolved O2

Front 45

HEMOGLOBIN

O2 Content = (Equation)?

Back 45

= (O2 Binding Capacity x %sat) + Dissolved O2

Front 46

HEMOGLOBIN

O2 Content is dependent on?

Back 46

- Hb Concentration

- Arterial pO2

- P50 of Hb

Front 47

Decrease in Hb Concentration

- causes what change to O2 Content?

- but what values will NOT change?

Back 47

- Decreases O2 Content

NO CHANGE w/:
- Arterial pO2
- % saturation

Front 48

Chronic Lung Disease affects arterial pO2 in what way?

MOA?

Back 48

- Chronic Lung Dz

- Physiologic Shunt
decreases O2 Extraction Ratio

Front 49

Define P50

What is the value of P50?

Back 49

pO2 @ 50% saturation

pO2 = 25 mmHg

Front 50

HEMOGLOBIN

O2 Delivery (to tissues) = (Equation)?

Back 50

= Cardiac Output x O2 Content