cardio 3.2

Question 1

in what two forms is oxygen carried in the blood?

Answer 1

• dissolved in plasma (about 1.5%)

- bound to hemoglobin (most important, about 98.5%)

Question 2

by how much does hemoglobin increase the O2 carrting capacity of blood?

Answer 2

by 70%

Question 3

what binds O2 in Hemoglobin?

Answer 3

Fe+2

Question 4

what does each hemoglobin sub-unit conatin?

Answer 4

a Heme Moiety

Question 5

Hemoglobin is also known by what other name?

Answer 5

alpha2beta2

Question 6

how saturated is hemoglobin in the arteries? (at a Po2 of 100mmHg)

Answer 6

98-100% saturated

Question 7

how saturated is Hemoglobin a Po2 of 40mmHg? (e.g. mixed venous blood)

Answer 7

about 75% saturated

Question 8

at what pressure is hemoglobin 50% saturated?

Answer 8

25mmHg (called P50) two of the four heme groups contains an oxygen

Question 9

what is the change of hemogobins affinity for oxygen called?

Answer 9

positive cooperativity this change in affinity facilitates the loading of O2 in the lungs and unloading of O2 at the tissues (steep portion of the curve)

Question 10

what four things influence the saturation of hemoglobin at a given Po2?

Answer 10

• Temperature
• Blood pH
• amound of 2,3-bisphosphoglycerate
• P(CO2)

Question 11

where is 2,3-BPG produced ?

Answer 11

in glycolosis as RBC break down glucose

Question 12

what causes shifts to the right on the dissociation curve? (decreased affinity for oxygent?

Answer 12

increases of:
   P(CO2)
   temperature
   2,3-DPG
decrease of 
    pH

Question 13

what is the bohr effect?

Answer 13

increases in P(CO2) of a decrease in pH shifting the dissociation curve to the right

Question 14

how does 2,3-DPG cause a shift to the right in the dissociation curve?

Answer 14

Binds to beta chains

Question 15

what happens to 2,3-DPG at high altitudes?

Answer 15

increased synthesis facilitates the unloading of O2 at the tissues

Question 16

what occurs when the dissociation curve shifts to the left?

Answer 16

• affinity for O2 is increased
• P50 is decreased (more dificult to unload O2 in tissue
• at any level saturation of hemoglobin is increased

Question 17

how much greater is Hemoglobins affinity for CO2 then O2?

Answer 17

200X

Question 18

does binding CO2 increase of decrease the affinity of hemoglobin for O2?

Answer 18

Increases the affinity

Question 19

Contrast hypoxemia vs hypoxia

Answer 19

Hypoxemia decrease in Arterial P(O2)

Hypoxia Decrease in O2 delivery to the tissues

Question 20

what are three causes of hypoxia?

Answer 20

• decreased cardiac output
• decreased O2 binding capacity of hemoglobin
• decreased arterial P(O2)

Question 21

what is Anemic hypoxia?

Answer 21

poor O2 delivery resulting from too few RBCs or from RBC that contain abnormal or too little Hb

Question 22

Ischemic (stagnant) hypoxia?

Answer 22

occcurs when blood circulation is impared (systemic of local)

Question 23

what is histotoxic hypoxia?

Answer 23

when the body cells are unable to use O2 even though adequate amounts are delivered (poisons)

Question 24

list hypoxemic hypoxia causes and indicator

Answer 24

indicated by reduced arterial P(O2)
abnormal ventalation-perfusion coupling
pulmonary diseases
breathing are with low O2

Question 25

what three forms does CO2 use to get to the lungs?

Answer 25

• dissolved CO2 which is free in solution (small amounts)
• carbominohemoglobin (CO2 bound to Hemoglobin)
• HCO3- (major form 70-90%)

Question 26

what causes chloride shift to occur?

Answer 26

HCO3- diffuses out of the red blood cell in exchange Cl- which helps maintain its osmotic equilibrium
OPPOSITE IN LUNGS

Question 27

what is the Ventilation-perfusion Ratio?

Answer 27

V/Q is the ratio of alveolar ventilation (V) to pulmonary blood flow (Q) important to achieve the ideal exchange of O2 and CO2

Question 28

what is the appoximate ratio when tidal volume, and cardiac output is normal?

Answer 28

V/Q ratio of approximately 0.8

Question 29

what Is the V/Q ratio when there is a SHUNT?

Answer 29

Zero (there is no gas exchange that perfuses but not ventilated)

Question 30

what is the V/Q ratio when the blood flow to the lungs is completerly blocked?

Answer 30

Infinate (known as dead space)