Gas transport - Quiz 5

Question 1

What is Tissue Oxygenation?

Answer 1

Process of moving O₂ & CO₂ in and out of body tissues

Question 2

Distance of diffusion before it gets too slow?

Answer 2

> 100 micrometers

Question 3

What are the Types of Hypoxia?

Answer 3

1. Hypoxic Hypoxia
2. Stagnant (Ischemic) Hypoxia
3. Anemic Hypoxia
4. Histotoxic Hypoxia

Question 4

What is hypoxic hypoxia

Answer 4

Not enough O₂ uptake from lungs to blood (Low PO2)

EX: COPD

Question 5

What is Stagnant Hypoxia

Answer 5

Ischemic Hypoxia (Low Perfusion)

Not enough blood flow to organ

EX: Arteriosclerosis PVD

Question 6

What is Anemic Hypoxia?

Answer 6

Not enough blood oxygen carrying capacity (Low HGB)

EX: Inactivated HGB

Question 7

What is Histotoxic Hypoxia

Answer 7

Inteference with Mitochondrial Respiration

Ex: Cyanide Poisoning

Question 8

What proteins carry the most O₂?

Answer 8

Hemoglobin

Normal: 150g/L or 15g/dL

Carries 65x more O₂ than plasma

Question 9

Hemoglobin Characteristics

Answer 9

4 subunits = 2 alpha + 2 beta

Four Heme Groups - Iron-Porphyrin at O₂ binding site

Question 10

What is the Normal Adult Hgb Configuration?

Answer 10

Normal Adult = HbA = a2B2

Question 11

What is the only thing that can bind to O2 in an iron containing porphyrin ring?

Answer 11

Ferrous Iron (Fe²⁺)

Question 12

How many goblin protein chains can each heme combine with?

Answer 12

One

Question 13

How much O₂ can each gm of Hemoglobin carry?

Answer 13

1.31 - 1.39 mL of O₂

Question 14

What is Oxyhemoglobin?

Answer 14

When O2 is binds with hemoglobin.

Binds reversibly

Question 15

How fast does binding and unbinding of Hgb to O₂ happen?

Answer 15

Milliseconds

Important for gas exchange

Loose bonds b/t Fe²⁺ & O₂

Oxygen carried in molecular state

Question 16

What is the shape of the HbO2 equilibrium curve?

Answer 16

Sigmoid

Rxn b/t four heme groups

Heme group’s O₂ binding capacity enhancement

Question 17

O2 Saturation = ? PaO₂

100% =

95% =

90% =

75% =

60% =

50% =

Answer 17

100% = 100

95% = 75

90% = 60

75% = 40 (mixed venous blood in pulm artery)

60% = 30

50% = 27

Question 18

Oxygen Hemoglobin Dissociation Curve:

pH: Up

CO₂: Down

DPG: Down

Temp: Down

Answer 18

Left Shift - Holds on to O₂ for greater transport

Question 19

Oxygen Hemoglobin Dissociation Curve:

pH: Down

CO₂: Up

DPG: Up

Temp: Up

Answer 19

Right Shift - Enhances release and uptake of O₂ (Bohr Effect)

Question 20

Ligands

Answer 20

Iron attracted more to ligands than to O₂

EX: Carbon Monoxide, Nitric Oxide

Question 21

What is the initial pressure difference that causes O2 to diffuse into pulmonary capillary?

Answer 21

104 - 40 - 64 mmHg

Question 22

What happens when O₂ is used by the cells?

Answer 22

Virtually all of it becomes CO₂ , increasing PCO2 –> causes it to diffuse to capillaries –> then to lungs to be expired

Question 23

Why does blood in the lung require less time to become fully oxygenated during exercise?

Answer 23

Diffusion capacity increases 3x due to increased surface area (recruitment)

Question 24

How is tissue PO₂ determined?

Answer 24

Balance between

Rate of O₂ Transport to tissues

and

Rate of O₂ used by tissues

Question 25

Why is the pressure difference needed for CO₂ diffusion **A LOT** less than that of O₂?

Answer 25

CO₂ diffuses 20x faster (Alveolar CO2 is 40, capillary CO2 is 45... only 5 mmHg difference)

Question 26

How much O₂ is carried by 100 mL of plasma?

Answer 26

0.003 mL of O₂

Question 27

What is the max amount of O2 can Heme carry in a normal man and woman?

Answer 27

Man: 20 mL O₂ per 100 mL of blood Woman: 19 mL O₂ per 100 mL of blood

Question 28

How many oxygen molecules can bind to Hemoglobin?

Answer 28

Four

Question 29

What is Oxygen Saturation?

Answer 29

Ratio of bound Oxygen to Total amt that can be bound to Hgb

Question 30

What is Oxygen Capacity

Answer 30

Max amount of O2 bound to Hgb

Question 31

What is shunt flow and how does it effect the blood entering the left heart?

Answer 31

The 2% of blood that came from aorta supplying the deep lung tissues. Mixes with pulm. venous blood dropping PO2 from 104 mmHg to 95 mmHg

Question 32

Carbon Monoxide

Answer 32

Iron attracted 250x more than it does Oxygen Doesnt separate readily Needs hours for body to get rid of it

Question 33

Nitric Oxide

Answer 33

Binds 200k times stronger **Irreversible** Binding Used to treat Pulm. HTN

Question 34

What is Methemoglobinemia?

Answer 34

Condition where the Hemoglobin CANNOT let go of oxygen Treat with Methylene Blue

Question 35

Which way does oxygen dissociation curve shift with PRBCs or stored blood?

Answer 35

Left Shift d/t decrease in DPG

Question 36

How to calculate O2 content (CaO₂) in blood?

Answer 36

**CaO₂ = (SO₂ x [Hgb] x 1.31) + (PO₂ x 0.003)** ## Footnote SO₂ = O₂ Sat (%)

Question 37

How to calculate Oxygen Delivery (DO₂)

Answer 37

CaO₂ x CO

Question 38

How do muscle cells, Myoglobin, relate to O₂

Answer 38

Has increased infinity for O₂ at **lower** PO₂ ​and Temporarily stores O₂ in muscle

Question 39

What reduces Hgb's ability to transport O₂?

Answer 39

Cardiac Output Anemia

Question 40

What is the volatile waste product of Cellular Metabolism

Answer 40

Carbon Dioxide

Question 41

What is converted to CO₂ to be exhaled in the lungs?

Answer 41

Carbonic Acid

Question 42

What is the Total Amount of CO2 transported in the blood?

Answer 42

200 mL/min of CO₂ made in resting adult x6 for exercise

Question 43

What is the average amount of CO₂ transported to lungs?

Answer 43

4 mL per 100mL of blood

Question 44

What is the function of the large amount of CO₂ that remains in the blood?

Answer 44

Bicarbonate Buffer Maintenance of Hydrogen Ion Concentration 85%

Question 45

CO2 Transport

Answer 45

1. Tissues use O₂ and Produce CO₂ 2. CO₂ + H₂O (Carbonic Anhydrase) --\> H₂CO₃ (Carbonic Acid) 3. H₂CO₃ splits into H⁺ & HCO_3- (Bicarb) 4. Bicarb exits cell, Cl^- enters to balance 5. Cell goes to Pulmonary Capillary 6. Cl^- exits and Bicarb Re-Enters 7. HCO_3- (Bicarb) + H⁺ --\> H₂CO₃ (Carbonic Acid) 8. Carbonic Anyhydrase splits H₂CO₃ --\> CO₂ + H₂O 9. CO₂ leaves cell and goes into Alveoli

Question 46

Bohr Effect

Answer 46

* Increase in CO₂ causes O₂ displacement * Right shift * Increase in H+ ion * Increase in Carbonic Acid

Question 47

Haldane Effect

Answer 47

* O₂ + Hgb displaces CO₂ from blood * Hgb is stronger acid, makes it less likely to combine with CO₂ * Releases exces Hydrogen Ions

Question 48

What is the metabolic arteriovenous O2 difference in Respiratory Gas Transportation?

Answer 48

50 mL/L

Question 49

What is the metabolic arteriovenous CO₂ difference in Respiratory Gas Transportation

Answer 49

40 mL/L

Question 50

What is the PO2 in the Tissue?

Answer 50

10 mmHg

Question 51

What is the PCO2 in the Tissue

Answer 51

50 mmHg

Question 52

Percentages of the Different Ways CO₂ is Transported

Answer 52

* CO₂: 7% * Hgb - CO₂: 23%^ * HCO₃^-: 70%