Respiratory IV Transport of O2 and CO2

Question 1

how is oxygen carried physically and chemically in the body

Answer 1

physically dissolved in blood and chemically combined to hemoglobin

Question 2

how is carbon dioxide physically and chemically carried in the body

Answer 2

physically dissolved in blood, chemically combined to blood proteins as carbamino compounds and as bicarbonate

Question 3

what do the partial pressure of the gases include

Answer 3

the gases that are dissolved in the plasma

Question 4

what happens to the gradient when cells utilize more oxygen than normal

Answer 4

the gradient increases which increases flow of oxygen from the blood to the tissues

Question 5

what is the tissue PO2 a function of

Answer 5

-the rate of O2 transport to the tissues in blood (blood flow)
- the rate at which the tissues use O2

Question 6

what does increased blood flow and/or increased metabolism result in with O2

Answer 6

more O2 delivery to the tissues

Question 7

what is the pressure in arteries of O2, CO2, and SO2

Answer 7

-O2: 95
-CO2: 40
- SO2: 97%

Question 8

what is the pressure in the capillaries of O2 and CO2

Answer 8

-O2: 40
CO2: 46

Question 9

what is the pressure in the veins of O2, CO2, and SO2

Answer 9

-O2: 40
-CO2: 46
-SO2: 75%

Question 10

without hemoglobin what would CO need to be in L/min to transport sufficient oxygen to meet the needs of the tissues at rest

Answer 10

83.3 L/min

Question 11

how much of the total oxygen content is dissolved in plasma

Answer 11

2%

Question 12

how much O2 reversibly binds to hemoglobin inside of the RBC

Answer 12

98%

Question 13

describe the hemoglobin molecule

Answer 13

2 alpha subunits and 2 beta subunits and each bind 1 molecule of O2

Question 14

what state must iron be in to bind O2

Answer 14

ferrous state

Question 15

what does the amount of oxygen bound to hemoglobin depend on

Answer 15

-plasma O2
- number of binding sites in RBCs

Question 16

what does the number of binding sites in RBCs depend on

Answer 16

the Hb amount per RBC

Question 17

how many Hb molecules does 1 RBC contain

Answer 17

1 million

Question 18

what is the concentration of oxygen in the arterial blood (definition)

Answer 18

ml of O2 carried by oxyhemoglobin plus ml of O2 carried dissolved in plasma

Question 19

what is the average g of Hb / 100 mL of blood

Answer 19

15 g Hb/100 mL blood

Question 20

what is the average partial pressure of oxygen in arterial blood

Answer 20

95 mmHg

Question 21

what is the average CaO2 ( number)

Answer 21

19.782 ml O2/100 mL blood

Question 22

what does 2,3-BPG do

Answer 22

binds to beta subunits of deoxy hemoglobin and decreases its O2 affinity which causes more oxygen unloading

Question 23

what is positive cooperativity

Answer 23

at a high PO2 hemoglobin’s affinity for O2 is highest

Question 24

when does a major drop off in % O2 saturation of hemoglobin occur

Answer 24

60 mmHg

Question 25

what is the bohr effect

Answer 25

the oxyhemoglobin dissociation curve shifts to the right

Question 26

what is a right shift/bohr effect caused by

Answer 26

-increased H+ ions - increased CO2 - increased temperature - increased BPG

Question 27

what does a right shift in the oxyhemoglobin dissociation curve indicate

Answer 27

decreased affinity between hemoglobin and oxygen

Question 28

when do levels of 2,3- BPG increase

Answer 28

with exercise, hypoxia from high altitude, pregnancy, and chronic lung disease

Question 29

what is the normal blood pH

Answer 29

7.4

Question 30

what is a left shift in the oxyhemoglobin dissociated curve caused by

Answer 30

- decreased PCO2 - increased pH - decreased temperature - decreased 2,3- BPG

Question 31

what does a left shift indicate about oxygen/Hb affinity

Answer 31

- increased affinity - O2 is less likely to dissociate from Hb

Question 32

how much of a greater affinity does CO have for Hb than O2 does to Hb

Answer 32

250x

Question 33

what is the effect of CO bound to Hb

Answer 33

increased Hb's affinity for O2 (left ward shift in curve)

Question 34

if CaO2 is greatly reduced, what happens to PaO2

Answer 34

could be normal

Question 35

what is the treatment for CO poisoning

Answer 35

-pure oxygen - 5% CO2

Question 36

what is the common presentation of CO poisoning

Answer 36

-cherry red skin - flu like symptoms - headache - neurologic symptoms

Question 37

what are the 3 variants of Hb

Answer 37

-methemoglobin - hemoglobin F ( fetal) - hemoglobin S (sickle cell)

Question 38

what happens in methemoglobin

Answer 38

-heme with Fe3+ (ferric) has lower O2 affinity and causes heme groups in the same Hb molecule with heme in the Fe2+ (ferrous) state to have higher affinity for bound O2 so net effect is less O2 release from Hb and less delivery to tissues

Question 39

what can methemoglobin occur due to

Answer 39

G6PDH deficiency or exposure to local anesthetics such as prilocaine or benzocaine

Question 40

describe the structure of hemoglobin F

Answer 40

2 alpha chains and 2 gamma chains

Question 41

describe the affinity of hemoglobin F to O2

Answer 41

higher affinity for oxygen than adult Hb because it doesnt contain the beta chain that binds to 2,3-BPG

Question 42

describe the structure of Hb S and what causes it

Answer 42

-normal alpha and beta units - caused by one amino acid change - when deoxygenated, RBCs form sickle shapes and obstruct small vessels

Question 43

describe Hb S affinity for O2 compared to normal adult Hb

Answer 43

O2 has lower affinity

Question 44

what is the oxygen content in methemoglobin compared to normal oxyhemoglobin

Answer 44

decreased by 50% so about 10

Question 45

what is hypoxemia

Answer 45

low PaO2

Question 46

what is hypoxia

Answer 46

low tissue O2

Question 47

what causes hypoxemia

Answer 47

-decreased FiO2 -hypoventilation - diffusion defects - V/Q defects

Question 48

describe the A-a gradient in decreased FiO2, hypoventilation, diffusion defects, and V/Q defects

Answer 48

-decreased FiO2: normal -hypoventilation: normal - diffusion defects: increased - V/Q defects: increased

Question 49

when is supplemental O2 helpful in hypoxemia causes

Answer 49

in every case

Question 50

what can hypoxia be caused by

Answer 50

hypoxemia, decreased cardiac output, anemia

Question 51

what are the PCO2 values in the alveoli, arteries, capillaries and veins

Answer 51

- alveoli: 40 -arteries: 40 -capillaries: 46 0veins: 46

Question 52

does hemoglobin transport CO2

Answer 52

yes

Question 53

what can CO2 be transported as in the blood and what are the percentages of each

Answer 53

-dissolved CO2: 7% - carbamino-hemoglobin: 23% - bicarbonate: 70%

Question 54

what is the volume of transport of CO2 in the blood

Answer 54

4 ml CO2 / 100 mL blood

Question 55

which is the slowest of the transport mechanisms of CO2 in blood

Answer 55

carbaminohemoglobin

Question 56

which is the fastest of the transport mechanisms of CO2 in blood

Answer 56

bicarbonate

Question 57

describe the carbaminohemoglobin transport mechanism

Answer 57

CO2 forms a loose, reversible bond with hemoglobin on terminal amine groups

Question 58

describe the bicarbonate transport mechanism

Answer 58

In RBCs, carbonic anhydrase rapidly forms carbonic acid from H2O and CO2 which in turn dissociates into H+ and HCO3- - H+ combines with hemoglobin for buffering and HCO3- moves into plasma in exchange for Cl-

Question 59

what is the haldane effect in systemic capillaries

Answer 59

deoxygenated Hb promotes increased binding of CO2 to Hb

Question 60

what would happen to PaCO2 if there were no carbonic anhydrase

Answer 60

it would increase by double

Question 61

what is the effect of CO2 with Hb at lower O2 concentrations

Answer 61

CO2 is more likely to combine with Hb and Hb buffers more H+

Question 62

what is the haldane effect in pulmonary capillaries

Answer 62

oxygenated Hb promotes dissociation of CO2 from Hb